NHF – new heroes for Heroes V 3.1.

The truth is, there is one huge drawback – you can’t choose the target for the attack with this bonus. Therefore, when the opponent starts playing with “stacks of one,” all the power of the specialization sometimes “goes to waste.”

And also, his special ability always targets the lowest-level stack. In few cities is the first level a crucial stack for the endgame. Unless it’s the Dungeon, but they are more likely to come with 2x7 Rogues and the intention to outsmart you.
By the way, it’s interesting how his special ability works against Ballistic Defense.