[D20 to GURPS] Burnt Offerings Conversions

[Dragondog]

Originally Posted by Landwalker

* Why is that? Shouldn't the fact that it is a follow-up to a melee attack make it a Melee Attack? Shouldn't it still need Blood Agent, since it only works if it penetrates the target's DR (I don't see anything in the Follow-Up enhancement description that says a successful "carrier attack" that hits, but which does no damage due to DR, still delivers the Follow-up effect)?

Perhaps I should have said, cannot have, rather than doesn't need, to make this clearer.

"A Follow-Up attack need only list its damage amount and type. All other details depend on the carrier attack." B105

Thus, if the carrier is a melee attack, the follow-up is also a melee attack and cannot have that limitation.

As both Follow-up and Blood Agent are "penetration modifiers" you can only have one of them.

* That's the intention. The mechanical goal is to allow the Wrathspawn to make two attacks per round: A DWA with both claws, followed by a Bite (which would use Brawling and be the Extra Attack in this case).

I'm not sure what kind of limitation that would be, not that it matters when constructing a NPC.

Affliction 1 [10 base] — Mild Wrath (-2 to DX, IQ, and Self-Control; halved for characters with Pacifism; automatically forces a Bad Temper roll for characters with that disadvantage) [+20%]; Follow-Up (Bite) [+0%]; Resisted by Will [+20%]; Symptom: Severe Wrath (As above, but -4 to rolls, and non-Pacifist characters cannot take All-Out Defense; 1/3 basic HP, x3) [+120%]; Symptom: Terrible Wrath (As Severe Wrath, but -6 to rolls, and non-Pacifists cannot make Defensive Attacks; 1/2 basic HP, x2) [+80%]; Symptom: Fury (As Terrible Wrath, but non-Pacifists also immediately suffer Berserk (with a base SC of 6, which causes automatic failure due to Terrible Wrath); 2/3 basic HP, x1) [+20%]

This way you will have Mild Wrath as soon as you are afflicted and only as long as the affliction lasts. When you've lost 1/3HP you will also have Severe Wrath which will last until you have more than 2/3HP even if the affliction and the Mild Wrath effect has ended by then. Severe Wrath will be replaced by more severe Wrath effects as you lose more HP.

Originally Posted by Kuroshima

Personally, I would create a new irritant condition, on the same scale than Pain (and with a single advantage or disadvantage that makes halves the penalties, in this case, I think that it would be Pacifism).

We'd also need a trait to double the effect. Bad Temper seems to be the best fit. Unless the limited choices balances that.

[Kuroshima]

Originally Posted by Landwalker

* Why is that? Shouldn't the fact that it is a follow-up to a melee attack make it a Melee Attack? Shouldn't it still need Blood Agent, since it only works if it penetrates the target's DR (I don't see anything in the Follow-Up enhancement description that says a successful "carrier attack" that hits, but which does no damage due to DR, still delivers the Follow-up effect)?

Blood Agent on a Follow-Up is worth -0%

* That's the intention. The mechanical goal is to allow the I like that solution a lot. It maintains the "increasing effect" feel of the original ability and seems to be pretty closely paralleling existing rules (which makes me more comfortable with it).

I might fiddle around with it just so that taking any damage from the Wrathful Bite would trigger "Mild Wrath," and then taking damage in excess of the various thresholds kicks it up a notch. Pending figuring out the Melee Attack / Blood Agent issue, something like this:

Wrathful Bite

Affliction 1 [10 base] — Mild Wrath (-2 to DX, IQ, and Self-Control; halved for characters with Pacifism; automatically forces a Bad Temper roll for characters with that disadvantage) [+20%]; Follow-Up (Bite) [+0%]; Resisted by Will [+20%]; Symptom: Severe Wrath (As above, but -4 to rolls, and non-Pacifist characters cannot take All-Out Defense; 1/3 basic HP, x3) [+120%]; Symptom: Terrible Wrath (As Severe Wrath, but -6 to rolls, and non-Pacifists cannot make Defensive Attacks; 1/2 basic HP, x2) [+80%]; Symptom: Fury (As Terrible Wrath, but non-Pacifists also immediately suffer Berserk (with a base SC of 6, which causes automatic failure due to Terrible Wrath); 2/3 basic HP, x1) [+20%]

Final Cost: [+36 Points]

With both Melee Attack (Reach C) [-30%] and Blood Agent [-40%], the Final Cost would be [+29 Points].

First, the Wrath levels should be priced as the pain levels, meaning that:

• Mild Wrath should cost +20% (as Moderate Pain)
• Severe Wrath should cost +40% (as Severe Pain)
• Terrible Wrath should cost +60% (as Terrible Pain)
• Fury should should cost +100% (As Agony)

If building this as a Character, the issue is that imposing Mild Wrath automatically requires quite a lot of levels of affliction. Also, instead of making it a followup, you could use the rules for modifying ST-based damage. Here's what I propose:

Thrust 1d-1->0.7d
As a crushing innate attack, this equals 0.7x5=3.5 points (Basic says you round up before, Psionic Powers says that you can skip rounding until the end, to avoid math issues with double roundups)

Modifiers:

• Accessibility, only on a single attack, -60%
• Symptoms, Severe Wrath, 1/3 HP lost (Only on targets afflicted by Mild Wrath, -40%), +72%
• Symptoms, Terrible Wrath, 1/2 HP lost (Only on targets afflicted by Mild Wrath, -40%), +72%
• Symptoms, Fury, 2/3 HP lost (Only on targets afflicted by Mild Wrath, -40%), +90%

Total: 174%
This is applied to the base of 3.5 points, but without counting the base 3.5 points, gives us:
3.5*(1+174/100)-3.5=3.5*1.74=6.09, rounded to [7]

You also take Toxic Attack, 30 points, equivalent to 0.25+29*0.3=8.95d, with the following enhancements:

• Follow-Up, Bite, +0%
• No Wounding, -50%
• Side Effect, Mild Wrath, +70%

Total +20%

8.95d of toxic damage with a +20% enhancement cost 8.95*4*1.2=42.96, rounded to [43], for a total cost of [50]

Mechanically, it works as follows:
When damaged by the wrathful bite, the target makes an HT-15 roll (and quite probably fails, though he can always resist with a 3 or 4, and this is a metabolic hazard, thus resistance to metabolic hazards applies), or gets afflicted with Mild Wrath for minutes equal to his margin of failure. If the bite does not penetrate, then as it's a toxic attack, it does causes no further effects, and does not try to penetrate DR on it's own. Also, keep track of the amount of damage caused by the wrathful bite. When it exceeds 1/3 of the character's HP, Mild Wrath gets updated to Severe Wrath, when it exceeds 1/2 of the character's HP, it gets updated to Terrible Wrath, and finally, when it exceeds 2/3 of the character's HP, it gets upgraded to Fury.

Statistics: Modified ST Damage, 1d-1 (Accessibility, only on a single attack, -60%; Symptoms, Severe Wrath, 1/3 HP lost (Only on targets afflicted by Mild Wrath, -40%), +72%; Symptoms, Terrible Wrath, 1/2 HP lost (Only on targets afflicted by Mild Wrath, -40%), +72%; Symptoms, Fury, 2/3 HP lost (Only on targets afflicted by Mild Wrath, -40%), +90%) [7]+Toxic Attack, 30 points (Follow-Up, Bite, +0%; No Wounding, -50%; Side Effect, Mild Wrath, +70%) [43]

[Dragondog]

Originally Posted by Kuroshima

If building this as a Character, the issue is that imposing Mild Wrath automatically requires quite a lot of levels of affliction. Also, instead of making it a followup, you could use the rules for modifying ST-based damage. Here's what I propose:

Where do you find the rules for modifying ST-based damage?

[Kuroshima]

Originally Posted by Dragondog

Where do you find the rules for modifying ST-based damage?

GURPS Powers p. 146

[Landwalker]

Well, that's a lot of stuff I'm not quite following. Let me try to walk through it and see if I can sort it out.

Originally Posted by Kuroshima

First, the Wrath levels should be priced as the pain levels, meaning that...

I believe that's what I did. The only difference I had in base modifier value was that Fury was priced as Berserk (Self-Control 6) and treated as a "Disadvantage-inducing Affliction" instead of as a parallel to Agony, which gave it a base modifier value of [+20%] based on B.36. Considering that Fury is basically "Goes Berserk" and doesn't override or erase the other wrath effects, I'm not seeing why it would be priced as anything other than a Disdvantage-inducing Affliction. Are you saying that Fury does override Terrible Wrath, and thus has to include all of the effects of Terrible Wrath in addition to the new effects of Fury (hence the high base cost)?

Originally Posted by Kuroshima

If building this as a Character, the issue is that imposing Mild Wrath automatically requires [emphasis mine] quite a lot of levels of affliction.

I'm afraid I'm not picking up on this. If we're treating Mild Wrath as analogous to Moderate Pain, I don't see any reason why it would require anything more than Affliction 1 and a Will-0 resistance roll. Why does it automatically require a high Affliction level?

Originally Posted by Kuroshima

Also, instead of making it a followup, you could use the rules for modifying ST-based damage.

Ah, thanks for beating me to asking for a page reference on this, Dragondog. God knows I wasn't going to find it on my own. Since the Wrathspawn's Bite attack is Cutting, not Crushing, shouldn't the base for going this route be (0.7d) * (7 points / level, B.61) = 4.9 points?

I also don't understand what the purpose or advantage is of doing this way instead of doing it as a Follow-Up to a normal, melee, natural unarmed attack. What does this route offer that the Follow-up route doesn't?

Originally Posted by Kuroshima

Symptoms, Severe Wrath, 1/3 HP lost (Only on targets afflicted by Mild Wrath, -40%), +72%

That seems like a pretty stiff limitation for something that can only be delievered by the same carrier as Mild Wrath in the first place, though I agree that if somebody resists the Mild Wrath affliction, they won't (or shouldn't) jump straight to Severe Wrath if they take additional damage without failing a resistance roll.

Originally Posted by Kuroshima

You also take Toxic Attack, 30 points, equivalent to 0.25+29*0.3=8.95d

Huh? From this point through the end (namely, what this has to do with Mild Wrath side effects), it's all going way, way over my head.

Sorry to be so clueless in all this, and I know that my bumbling must be getting tired (it certainly is getting tired for me!), but it's tough trying to tackle some of these things without any significant prior experience with all of the many and scattered parts of GURPS that you need to construct them.

Naturally, I have other questions, but those can wait. Baby steps...

[Kuroshima]

Originally Posted by Landwalker

Well, that's a lot of stuff I'm not quite following. Let me try to walk through it and see if I can sort it out.

Ok, no problem.

I believe that's what I did. The only difference I had in base modifier value was that Fury was priced as Berserk (Self-Control 6) and treated as a "Disadvantage-inducing Affliction" instead of as a parallel to Agony, which gave it a base modifier value of [+20%] based on B.36. Considering that Fury is basically "Goes Berserk" and doesn't override or erase the other wrath effects, I'm not seeing why it would be priced as anything other than a Disdvantage-inducing Affliction. Are you saying that Fury does override Terrible Wrath, and thus has to include all of the effects of Terrible Wrath in addition to the new effects of Fury (hence the high base cost)?

Simple cost symmetry. Still, the ability to cause Berserk instantly all the time should be giving the following disadvantage:

Berserk (N/A) (Battle Rage, +50%) [-37] (Resisting with N/A means you auto-fail, and it's x2.5, as per Powers p. 106). Still, being forced into Berserk, with no chance of snapping out (meaning that you WILL attack your friends after you finish your foes, untill you kill them or you) is well worth +100% as an affliction IMHO, and the price difference is so small, that I liked I had the whole ability for 50 points exactly ;)

I'm afraid I'm not picking up on this. If we're treating Mild Wrath as analogous to Moderate Pain, I don't see any reason why it would require anything more than Affliction 1 and a Will-0 resistance roll. Why does it automatically require a high Affliction level?

Ah, I though you wanted anyone bitten to get Mild Wrath automatically, with no resistance roll.

Ah, thanks for beating me to asking for a page reference on this, Dragondog. God knows I wasn't going to find it on my own. Since the Wrathspawn's Bite attack is Cutting, not Crushing, shouldn't the base for going this route be (0.7d) * (7 points / level, B.61) = 4.9 points?

No, you always calculate based on your thrust damage, and as a crushing attack. You're already paying for your bite damage being cutting when you buy shap teeth

I also don't understand what the purpose or advantage is of doing this way instead of doing it as a Follow-Up to a normal, melee, natural unarmed attack. What does this route offer that the Follow-up route doesn't?

How else do you add Armor Divisor to your punches, for example?

That seems like a pretty stiff limitation for something that can only be delievered by the same carrier as Mild Wrath in the first place, though I agree that if somebody resists the Mild Wrath affliction, they won't (or shouldn't) jump straight to Severe Wrath if they take additional damage without failing a resistance roll.

Well, you can argue that the limitation might be a little too large, but hell, we're speaking about minuscule amounts of points here, and it costs 43 points to almost ensure that any successful attack will trigger Mild Wrath. Also, Mild Wrath is much easier to remove with Healing (Cure Affliction), and removing it will cancel all the symptoms (that would otherwise be irremovable until the damage was healed)

Huh? From this point through the end (namely, what this has to do with Mild Wrath side effects), it's all going way, way over my head.

Well, Affliction is mostly overpriced if you want to take multiple levels, so I had to find a way to give Mild Wrath to the target in a way that reduced his chances to resist as much as possible. Doing it as a Toxic Innate Attack (that has the cheapest cost per dice, and that on top, works as if it had blood agent when combined with Folloup) was the easiest way to do it. Still, let's deconstruct it:

30 points of damage =>8.95d, is a direct application of the partial dice rules: The first point costs 0.25d, and any extra points cost 0.3d. You follow me right?

Ok, then I add no wounding (meaning that the wounding modifier is x0) and Side Effect (meaning that the target must check at HT-half the penetrating damage, or suffer an affliction effect). The thing is, Side Effect does not care about wounding modifiers, it cares about penetrating damage, that is, damage after DR and before wounding modifiers. As I said, Toxic damage is special, in the sense that it doesn't try to penetrate DR independently if the carrier doesn't penetrate, but as a Follow-Up if the carrier penetrates, then all the damage is penetrating damage.

The net effect is that anyone who gets bitten must, on top of the damage inflicted by the bite, make an HT roll against half the penetrating damage of the Follow-Up, but we've already stated that if ANY damage penetrates, then ALL damage penetrates, and otherwise, NO damage penetrates. Since the damage is exactly 30, then the exact penalty to resist is -15, every time.

Sorry to be so clueless in all this, and I know that my bumbling must be getting tired (it certainly is getting tired for me!), but it's tough trying to tackle some of these things without any significant prior experience with all of the many and scattered parts of GURPS that you need to construct them.

Naturally, I have other questions, but those can wait. Baby steps...

Don't worry. This is why I said that you don't need to build it as a PC, unless it's needed as a PC. Now, to me, it served as practice in ability building and SJG style writeups, but then again, I sometimes get some crunchy articles published on Pyramid ;)

[Landwalker]

Simple cost symmetry. Still, the ability to cause Berserk instantly all the time should be giving the following disadvantage:

Berserk (N/A) (Battle Rage, +50%) [-37] (Resisting with N/A means you auto-fail, and it's x2.5, as per Powers p. 106). Still, being forced into Berserk, with no chance of snapping out (meaning that you WILL attack your friends after you finish your foes, untill you kill them or you) is well worth +100% as an affliction IMHO, and the price difference is so small, that I liked I had the whole ability for 50 points exactly ;)

That makes sense. I'd forgotten that disadvantages could have "N/A" as a self-control number. Although, pin this to the board for a follow-up question coming shortly.

How else do you add Armor Divisor to your punches, for example?

My ig'nant self would have just used a straight Innate Attack and modified it from there, I suppose. Of course, my ig'nant self would have also made it a Cutting Innate Attack (for clawed/toothy such attacks, that is).

In this case, though, I guess my question can more specifically be, "Is there anything related to this specific special attack that lends itself better to the Modifying ST-Based Damage rules rather than the Follow-Up Affliction rules?"

30 points of damage =>8.95d, is a direct application of the partial dice rules: The first point costs 0.25d, and any extra points cost 0.3d. You follow me right?

Okay, I see where you're getting this now. So far, so good, and I get where you're going with the rest of the modifiers (No Wounding, Side Effect), so I think I'm solid on how you put that together now, and I get how you figured all the Symptom-based stuff.

So, bearing in mind that I don't actually want the Mild Wrath to be an automatic effect, I think this is where the ability currently stands:

Wrathful Bite: Modified ST Damage, 1d-1 (Accessibility, only on a single attack, -60%; Symptom, Severe Wrath, 1/3 HP Lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Terrible Wrath, 1/2 HP lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Fury, 2/3 HP lost [Only on targets afflicted by Mild Wrath, -40%], +90%) [7 Points] + Affliction 1, Mild Wrath (Follow-Up, Bite, +0%; Sense-Based, Will, +20%) +40% [12 points]

Mechanics: When damaged by a bite attack, the Target makes a Will-0 roll. Failure causes the Mild Wrath condition for minutes equal to margin of failure. If the bite does not penetrate, then, as a follow-up attack, it has no further effect. As the character accumulates Wrathful Bite damage, the symptoms go into play and persist indefinitely until the injuries are healed.

Now, assuming that's correct, it's time for that follow-up question I alluded to earlier, in two parts:

(1) How would this change if I wanted the symptoms to have the same limited duration as the Mild Wrath base?

(2) Does it even matter, since it seems to me that if Mild Wrath expires, then the subsequent conditions would expire as well?

(Not that that matters, either, I don't imagine. Someone who is afflicted with Fury for even one minute is probably still going to be frothing-at-the-mouth crazy when your average combat is over until his allies manage to subdue him.)

Now, to me, it served as practice in ability building

And that's exactly what I'm shooting for, so that when I really do have to build these crazy things for PCs, I'll be able to. Otherwise I'd just say "Eh, have some ability penalties because you're really angry now." But, after all, practice makes slightly-less-imperfect!


-------

Post-Script Question: Based on these rules, would Fury go into effect before or after the victim's HT roll to stay conscious for hitting 0 HP?

[Kuroshima]

Originally Posted by Landwalker

That makes sense. I'd forgotten that disadvantages could have "N/A" as a self-control number. Although, pin this to the board for a follow-up question coming shortly.

My ig'nant self would have just used a straight Innate Attack and modified it from there, I suppose. Of course, my ig'nant self would have also made it a Cutting Innate Attack (for clawed/toothy such attacks, that is).

In this case, though, I guess my question can more specifically be, "Is there anything related to this specific special attack that lends itself better to the [b]Modifying ST-Based Damage[/i] rules rather than the Follow-Up Affliction rules?"

You can't use symptoms with Afflictions. Hell, Afflictions are plain not worth using if you can use side effects and symptoms.

Okay, I see where you're getting this now. So far, so good, and I get where you're going with the rest of the modifiers (No Wounding, Side Effect), so I think I'm solid on how you put that together now, and I get how you figured all the Symptom-based stuff.

So, bearing in mind that I don't actually want the Mild Wrath to be an automatic effect, I think this is where the ability currently stands:

Wrathful Bite: Modified ST Damage, 1d-1 (Accessibility, only on a single attack, -60%; Symptom, Severe Wrath, 1/3 HP Lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Terrible Wrath, 1/2 HP lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Fury, 2/3 HP lost [Only on targets afflicted by Mild Wrath, -40%], +90%) [7 Points] + Affliction 1, Mild Wrath (Follow-Up, Bite, +0%; Sense-Based, Will, +20%) +40% [12 points]

Use 1 point Toxic Follow-Up instead of the affliction, as otherwise, the target would have to make the Will roll to even if the attack doesn't penetrate, though he would get a bonus equal to DR. Also, it's cheaper this way:

Toxic Attack, 1 point (Based on a Different Attribute, Will, +20%; No Wounding, -50%; Side Effect, Mild Wrath, +70%) [2]

Mechanics: When damaged by a bite attack, the Target makes a Will-0 roll. Failure causes the Mild Wrath condition for minutes equal to margin of failure. If the bite does not penetrate, then, as a follow-up attack, it has no further effect. As the character accumulates Wrathful Bite damage, the symptoms go into play and persist indefinitely until the injuries are healed.

Small nitpick, but you should track the Wrathful Bite damage even if they resist the affliction, as until they're healed, any time they get afflicted with Mild Wrath, they suffer the symptoms.

Now, assuming that's correct, it's time for that follow-up question I alluded to earlier, in two parts:

(1) How would this change if I wanted the symptoms to have the same limited duration as the Mild Wrath base?

See above, this build already makes the symptoms last only for as long as the Mild Wrath base lasts (but inflicting a new Mild Wrath reactivates the symptoms, so if you've suffered let's say, 7 points of Wrathful Bite and you've got 10 HP, then anything that causes you Milt Wrath trigger Fury)

(2) Does it even matter, since it seems to me that if Mild Wrath expires, then the subsequent conditions would expire as well?

(Not that that matters, either, I don't imagine. Someone who is afflicted with Fury for even one minute is probably still going to be frothing-at-the-mouth crazy when your average combat is over until his allies manage to subdue him.)

Egg-zactly, unless you toss some reduced duration on the affliction (This was canonized in Psionic Powers). Toss in Fixed Duration if you want (+0%, gives you MoF 3, regardless of the actual MoF, so combined with Reduced Duration 1/60 would get you 3 second bursts of anger).

And that's exactly what I'm shooting for, so that when I really do have to build these crazy things for PCs, I'll be able to. Otherwise I'd just say "Eh, have some ability penalties because you're really angry now." But, after all, practice makes slightly-less-imperfect!

Glad I could help, trust me, I got myself a lot of practice with afflictions when writing the Auras of Power article.

Post-Script Question: Based on these rules, would Fury go into effect before or after the victim's HT roll to stay conscious for hitting 0 HP?

I would say that after as the HT roll is instantaneous when you hit 0 or less FP, and the follow-up only fires after the attack penetrates. Still, it's open to GM interpretation (I used to know the timing rules for MtG like the back of my hand, back in the times of 4th-7th edition, when I played, so my view might be biased by that)

[Landwalker]

Use 1 point Toxic Follow-Up instead of the affliction, as otherwise, the target would have to make the Will roll to even if the attack doesn't penetrate, though he would get a bonus equal to DR.

That was the reason behind me originally giving the affliction Blood Agent. I'm still not clear why the Follow-up + Blood Agent combination doesn't fly.

So, assuming that Follow-up + Blood Agent isn't the way to go with this, the final version of Wrathful Bite would be:

Statistics: Modified ST Damage, 1d-1 (Accessibility, only on a single attack, -60%; Symptom, Severe Wrath, 1/3 HP Lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Terrible Wrath, 1/2 HP lost [Only on targets afflicted by Mild Wrath, -40%], +72%; Symptom, Fury, 2/3 HP lost [Only on targets afflicted by Mild Wrath, -40%], +90%) [7 Points] + Toxic Attack, 1 point (Based on Will, +20%; No Wounding, -50%; Side Effect, Mild Wrath, +70%) [2 points]

Total Cost: 9 CP.

That makes the Wrathspawn's total write-up as follows:

Spoiler:  

Wrathspawn (296 Points)

SM: +0

ST: 12
DX: 11
IQ: 10
HT: 12

HP: 15
FP: 12

Will: 10
Per: 11

Basic Speed: 6.00
Basic Move: 5

Advantages: Acute Sense (Smell Wrath) 2; Wrathful Bite (As Above); Claws, Talons; Combat Reflexes; Damage Resistance 2 (Tough Skin); Dark Vision; Detect Wrath (Precise); Extra Attack (Brawling); Magic Resistance 1; Night Vision 9; Regeneration (Very Fast, Takes Extra Time 1 — 1 HP / 2 seconds); Resistant (Immunity to Mind Control); Silence 2; Teeth, Sharp

Disadvantages: Appearance (Monstrous)

Skills: Brawling 13; Stealth 16

Techniques: Dual-Weapon Attack (Brawling) 13

Attacks
Talons [Skill 13, Parry 10; 1d-1 cut / 1d-1 imp; Reach C]
Bite [Skill 13, Parry 10; 1d-1 cut; Wrathful Bite]

Equipment
None

Notes

These suckers are going to be a right pain for an unlucky or ill-prepared PC, but fortunately some decent armor will set them in order.

Now that that's out of the way, I am free to tackle the next obstacle: A Vargouille...

[Dragondog]

Originally Posted by Landwalker

That was the reason behind me originally giving the affliction Blood Agent. I'm still not clear why the Follow-up + Blood Agent combination doesn't fly.

If you read the descriptions of Follow-up and Blood Agent, you'll see that both of them are "penetration modifiers," as I mentioned earlier. And a trait can only have one "penetration modifiers."