Sorcery: Power Within

In-Game Art

Pyromancy of Carmina, who harnessed the power of flame to actualize the inner-self. strength/endurance boost, but lose HP. Excessive power eats away the life-force of its caster, and like all dangerous spells, Power Within was kept secret for eons.

Power Within is a buff spell from Dark Souls considered a member of the Pyromancy class of magic. It comes with the terrifying drawback that it can very well kill you if used. Today I will model this using Sorcery.

Statting and Combining the Components

Dark Souls often uses relative buffs based off of percentages of a whole, whereas GURPS uses constant buffs. This means we have to choose  a value, and hope it is the right scale. For someone else, my values may be too high or too low, but that's up to you. I interpret 40% stronger to mean +8 striking strength. This benefits thrust and swing greatly. Endurance Boost sounds like Regeneration Fast (FP only). The total value of those two combined into one advantage is 90 points. The other important part is that the spell kills you by draining 100% of max HP over the course of 100 seconds. For the sake of GURPS, I think it might be better to say it takes an average person from HP to -HP over the course of 100 seconds. This is easy to model as a Cyclic Attack that does 2 Irresistible HP of damage every 10 seconds for a duration of 100 seconds. This can be modeled as a limitation on a limitation, Starting with Costs 2 HP, which is worth -20%, 10 doses each 10 seconds apart is +500% 6 times -20% is -120%.

The Buff Effect is the two of Striking ST 8[40] and Regeneration Very Fast (FP Only +0%)[100]

Power Within Buff (-80%): (Mana Sensitive -10%; Costs 2 HP, Cyclic, 10 cycles, 10 Seconds -120%) [28]
Note that maximum limitation discount is limited to -80% even though we greatly exceeded that. Someone who might want to do some min-maxing might find some value to squeeze into the -50% that we don't have access to.

Now that we put that together, we actually need to create a sorcery that gives us this advantage.

Power Within (+355%): Affliction(Sorcery -15%; Advantage, Power Within Buff +280%; Reach, Melee -30%; Malediction +100%; Extended Duration 1, +20%; Fixed Duration, 100 seconds +0%) [46]

Notes

This is a pretty powerful ability with a big drawback. As it is written, it is slightly divorced from the original effect. This one can be used on anyone at melee range. I think to limit it only to allies, you might add another -5% (Bringing us down to a whopping 45 points) and to limit to self, I might rewrite the buff with extended duration 1 +20% and fixed duration (100 seconds), and Change Mana Sensitive to Sorcery. The ability would then not be an affliction ability and would cost 28 points.