Chronoshift

You touch a willing creature within range apart from yourself. If the creature was to drop to 0 Hit Points while the spell is in effect, it regains a quarter of its Maximum Hit Points instead, rounded up and the spell ends. If the creature was to die while the spell is in effect, it becomes unconscious and stable instead and the spell ends.

If this spell is cast at 6th level, the creature regenerates half of its Maximum Hit Points instead. If it is cast at 8th level, it against all of its Hit Points instead.