A Tier-system for a DF setting

[Varyon]

After a break due to Real Life Stuff, I'm back to working on my Oubliette setting for DF. One of the components of that is a Tier system, inspired in part by the tiers of gear (and enemies) in games like Diablo II. I'm trying to figure out appropriate pricing for increasing Tier, and as my enchantment system is going to be a modified version of GURPS Meta-Tech, that means I need character point values.

Briefly, there are 5 Tiers. Null Tier weapons and armor are basically available for free to adventurers (discussed in this thread, although the Tier names have changed since then - Tier 0 then is Null Tier now, while Tier 1 then is Tier 0 now). Tier 0 weapons and armor are generally the mundane ones, although a lot of magic items are also Tier 0, and all the characters are Tier 0 (although there are magic items that can boost your personal Tier). Tiers 1 through 3 are found on more advanced magic items. As for monsters, those in the uppermost levels of a dungeon are typically Null Tier (these also tend to make up the bulk of raiding parties, as Null Tier's can survive outside the dungeon longer than higher-Tier monsters), with Tier increasing the deeper you go (note most dungeons don't go deep enough for Tier 3; indeed, the bulk of dungeons don't get beyond Tier 1 before they are destroyed by adventurers, and many are destroyed while still at Tier 0).

Tier influences the effectiveness of attacks and similar (as all Affliction-type effects are actually No Wounding Side Effects, this also means the Tier will influence how difficult they are to resist). Against a target who is wearing either no armor or armor that matches with their personal Tier, you subtract their Tier from that of your weapon (your personal Tier if attacking fully unarmed, the Tier of your armor if you're striking with it, such as for a kick with boots on) and consult the later table (which basically just adjusts things as per SSR). Null Tier is treated as Tier -2 when up against Tier 0, Tier -1 otherwise (meaning Tier 0 and Tier 1 gear are both equally effective). Null Tier monsters are also not terribly effective even when wielding higher-Tier weapons, giving an effective -1 to their weapon's Tier while wielding it (so a Null Tier with a Tier 0 sword would treat it as Tier -1).

For foes wearing armor of a different Tier than their personal one, the Tier difference is calculated in reverse (Armor Tier minus Weapon Tier) and adjusts the value of the armor. Penetrating damage is modified based on the target's personal Tier.

ΔTier	Multiplier
-4	x0.2
-3	x0.3
-2	x0.5
-1	x0.7
+0	x1
+1	x1.5
+2	x2
+3	x3
+4	x5

...

With that all out of the way... what's appropriate for pricing? We'll ignore Null Tier, at least for now, as the items are functionally free anyway and Null Tier monsters can't be PC's, Allies, or Enemies (actually monsters in general can't be any of these outside of specific campaign concepts, considering they're restricted to being in or near their dungeon of origin; Liminals, which are monsters that are free of the dungeon, certainly can be, but those are all Tier 0 anyway). For items that modify personal Tier (which would be the easiest to calculate for), you're essentially looking at Injury Tolerance: Damage Reduction combined with an equal Damage Multiplier effect. The first we know the price of - it's essentially [25] per -1 SSR to damage - but what of the second?

It's typically stated that defenses in GURPS cost around 3.5x as much as offenses, but I disagree. That's based on Innate Attack 1d [5] vs DR 1 [5], but at [5] that Innate Attack can only deal one of burning, crushing, or piercing damage, while at [5] that DR 1 defends against all of those, and every other damage type in the mix. Roughly speaking, an Innate Attack that can freely change to any type of damage is probably worth somewhere around [20] per 1d*. With that in mind, they're actually rather close in pricing** - DR 4 [20] vs Innate Attack (all) 3.5 [20] (in fact, before doing the analysis below I thought a fair price for IA (all) would be somewhere between [15] and [20], and DR 3.5 [17.5] is right smack-dab in the middle of those two).

With that in mind, I'm thinking that, at least for the Tier system presented here, setting Damage Multiplier at the same price as equivalent IT:DR would be appropriate, for [50] per full +1 to Tier ([25] for the defense side and [25] for the offense side). An argument can be made that it should be higher, considering any innate DR the character has would also benefit, but I'm inclined to waive that - I don't think I'm going to allow for innate DR that gets much above DR 2 (an exception may be made for some Liminals, but I'll cross that bridge when I come to it).

So, with a price for a boost to Tier for the character established, how should this behave for gear? Meta-Tech has an optional rule that traits that apply to the item rather than to the character can be taken at 1/5th cost, for [10] per +1 Tier, but part of me feels that's a bit too low of a price. For an amulet that just grants the character some ability, where the Tier simply makes it less susceptible to being broken***, that's probably fine. But for weapons that cause more damage, and armor that has higher DR, that doesn't seem quite right. Maybe I should still charge full cost for the defense side and 1/5th for the offense side for armor, and reverse these for weapons? That would mean, while most gear only calls for [10] per +1 Tier, weapons and armor call for [30] each. Does that make sense?

*Piercing throws things off by having 4 different sizes, but considering the use cases for things below Pi++ if you have access to Pi++ are rare, we'll only calculate it for Pi++. So this would be an Alternate Attack setup of burn ([5]), corr ([10]), cr ([5]), cut ([7]), fat ([10]), imp ([8]), pi++ ([8]), and tox ([4]). That's [1+10+1+1.4+2+1.6+1.6+0.8] = [19.4], rounding up to [20] - or [21] if you insist on rounding before adding them together.

**As an aside unrelated to the Tier system, you could use this to argue for DR pricing against a particular threat to be the same as the base cost for that threat. So DR that only protects against Cutting damage would cost [7] per 1d protection, or [2] per DR 1. Just something to consider...

***I'm also considering having some enchantments have a minimum Tier. Something that lets you fly, for example, might be required to be Tier 1 or higher. I haven't yet made up my mind on that, however.