(1/encounter) when you are reduced to 0hp, gain Temp HP equal to half your max HP. If you have the Deathwalk ability, you may choose which one to use (not both, as temp hp cannot stack).

You can treat Temp HP as max HP for your Undying Might feature, expending it in the process.

(KEY/encounter) Cause an attack to deal only 10 damage, then gain temp HP equal to the difference.

While dying, you can use Undying Might as a free action, but only by expending Temp HP.

(1/safe rest) when reduced to 0 wounds, become encased in a block of ice and immune to all damage and conditions. At the start of your next turn, heal all wounds and gain temp HP equal to 2x your max HP.