Omniscience Dragon, Hrimthurs (RRR)

[Stride]-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] Stride this card on your (VC) from face down.
[AUTO](VC):[Soul Blast (1)] At the end of the battle that this unit attacked a vanguard, you may pay the cost. If you do, choose one of your rear-guards, and it gets [Power]+4000 until end of turn. Then, you may have that unit get [Power]+4000 until end of turn. If you do, at the end of that turn, retire that unit. If the [Power] of the unit chosen with this effect is 20000 or greater, draw a card.