"Perform an attack targeting your Reanimate's space with a magic weapon. This attack gains blast. You do not need range or line of sight to the space. After the attack is resolved, the Reanimate is defeated."
I played this card recently to very good effect, but I made a mistake. I moved my Reanimate so they were adjacent to 4 monsters, and then I used this card, killing two monsters outright. I had assumed that corpse burst was to be used as an action of the Reanimate and not the Hero. When I subsequently attempted to make two attacks with my Hero, I was mightily rebuked. I had missed my chance to attack with my Reanimate, and my Hero had only one action left. In the end, my remaining action was enough to take out my target monster, who was carrying an item to the exit for victory, and the game was won by our adventurers. Hurrah!
But back to the point: In principle, I do agree that the action should be that of the Hero. There are two salient clues. "With a magic weapon" which a reanimate does not have and "You do not need range or line of sight to the space" which, again, seems to imply the Hero can perform this attack from any location. Still, in spite of these two strong implications, whoever's action it is - Reanimate or Hero - the card is manifestly unclear. It does not categorically state who's action is consumed. One could argue not unreasonably that, since it is the Reanimate who is expending itself, it is his/her/its action.
Anyway, I was curious to know if any other players noticed this point, and how they interpret it.
I would also like to state as an aside, that Widow Tarha is an awesome character. Lots of flexibility and a heavy hitter. Can take out whole groups of monsters.