[AUTO](RC):When this unit attacks a vanguard, if your vanguard is
Legion
, until end of that battle, this unit gets [Power]+2000, and
"[AUTO](RC):[Counter Blast (1) & Soul Blast (1)] When this unit's attack hits, you may pay the cost. If you do, reveal the top card of your deck, choose one of your opponent's rear-guards with the same grade as that card, your opponent puts that unit on the bottom of his or her deck, and you draw a card."
.
It is not necessary for all to hit. A single hit would blow to smithereens.