Sword Light Dragon, Skylizen (RRR)

[AUTO]:When this unit is placed on (RC) or put on (GC), choose up to one grade 4 card from your hand, and reveal it. If you revealed a card, or your vanguard is grade 4, perform one of the following according to the circle this unit is on.
•(RC)-Choose two of your rear-guards, and they get "Boost" until end of turn.
•(GC)-This unit gets [Shield] +15000 until end of that battle.
[AUTO]:When this card is discarded from hand while riding a grade 3 from the ride deck or paying the cost for [Stride], draw a card.