If we wanted to keep it, I'd suggest changing it to "dropped to zero" instead of killing blowed. Otherwise, it's a level 5 class ability that's not going to get used very much. I mean, the incentive is to not die, after all.
Maybe not a typo, but for consistency: Demon racial extra costuming power mentions 'redirect' use on spells once per mod. This is functionally the same as 'divert magic,' and 'redirect' has a different definition. I propose changing the wording to 'divert magic.'