Living Dead: 120s CD, 10s Duration

After receiving Fatal damage be restored to full health.

Pros

Shortest Immunity CD
Full heal afterward is potentially more healer-friendly than even Hallowed
Fills a slot for mitigation on DRK that the job could use

Cons
Very much so a 'use it well or get wrecked' ability. Mistiming it or dying ahead of time would be not so good. Mitigated by popping it late.
Useless against multi-hit attacks

Or something like that. Honestly it'd be a very different take on an immunity that would be kinda bad in some circumstances where you're getting hammered with damage but it working as a self-bene on a short CD would also be pretty good. A lot of the benefits of Holmgang only you trade the 7s duration for a full heal. Maybe change the name to something like 'Rise Again' or something edgy but more descriptive.

I didn't wanna read through all 8 pages before this though so someone might have already described a solution similar to this.