[Varyon]

Originally Posted by Mithlas

Unkillable 1 (p95) never has to roll to avoid death is definitely fitting

It also means you can keep going until your body is physically incapable of functioning (-10xHP), which seems rather appropriate here.

Originally Posted by Mithlas

Regeneration: Very Fast (p80) at least, but only for healing wounds from non-silver sources. Those heal slower, perhaps at standard rate

GURPS Horror has the Bane Limitation, which can be applied to Advantages like Regeneration to make them not apply to damage caused by certain materials (in your case, silver). Worth a look.

Originally Posted by Mithlas

Regrowth (p80) could potentially apply, but none of the plot milestones ever deal with him having limbs chopped off. Most of his major injuries are impaling.

Decide if he can actually regrow bits, or if the bits can simply never be chopped off in the first place. The latter is a form of Injury Tolerance found in GURPS Powers.

Originally Posted by Mithlas

Resistant (impaling damage. common?) (p81) some manner of dividing mundane damage could help maintain a degree of parity with his compatriots, as he's joined by other humans who fight and are injured alongside him
Resistant (piercing damage. common?) (p81)

The Advantage you're looking for here is Injury Tolerance: Damage Reduction (which you might see on the forum mentioned as IT:DR). It's basically Vulnerability, but in reverse - see GURPS Powers.
To have it apply to two different types of damage, I'd personally figure out how much it would cost to be resistant to a larger class that includes those two, then mark it somewhere logical that's in between. Physical Damage would be Very Common and would include Crushing, Cutting, Impaling, and Piercing (Burning is more Energy, Corrosion and Fatigue are fuzzier but I'd probably lump them with Energy). I don't feel like looking up the actual values, but for sake of argument let's say IT:DR (Very Common) costs [40], IT:DR (Common) costs [30]. That's [+10] for +3 damage types, so each damage type is [+3.33] or so; IT:DR (imp and pi) would thus cost [34].

Alternatively, just give him Injury Tolerance: Unliving, which has built-in resistance to piercing and impaling attacks. In GURPS, what something does is more important than what it's called - while the character may indeed be alive, the fact that he lacks many of the vulnerabilities of the living makes this trait appropriate.

Originally Posted by Mithlas

Damage Resistance (p47) while he's less likely to be stopped by mundane damage, I'm hesistant to use a straight subtractor because he can still be bruised and injured with the rest of his compatriots. Something more like "halves incoming damage" would seem more fitting because it would stop less lower-level damage but provide more protection against massive damage

Again, IT:DR. In this case, you might be looking at unmodified IT:DR or IT:DR (Physical Only), with further levels of the trait against impaling and piercing damage.

Originally Posted by Mithlas

Vulnerability (p161) multiplies the damage from that source, which is appropriate regarding the pain/shock taken from silver but doesn't reflect the fact that a 1kg straight-edged short sword would still only cut to a certain depth in the same swing.

Penetration is represented by basic damage, which Vulnerability doesn't modify. Your character isn't being cut any deeper by that silver sword, but the cut is hurting him more.

Originally Posted by Mithlas

Weakness (p161) bypasses defensive abilities, but causes damage at a distance like a radioactive isotope and doesn't reflect that it has to touch him.

I think Weakness can be modified to require you to actually touch the object (actually, I thought it did that to start with, but I don't have my Basic Set books with me). Also, decide if it should actually harm him simply with a touch (It Buuuuurnsss!), or if it needs to hit him with enough force to cause injury.


Another trait you might want to consider (although I think it comes "free" with Unliving - you'll want to check) is Injury Tolerance: No Blood to represent the fact that he can't bleed out. He might actually have blood, making him susceptible to Blood Agents and similar. I believe that is a -40% Limitation on IT: No Blood (reducing its price to [3]).