Ultimate Buddy!

<Generic> Choose one of your rear-guards, and put this card into that unit's Buddy Soul. [CONT]:If this card is in your rear-guard's Buddy Soul, that unit gets "[CONT]:[Soulguard] (When this unit would leave a (RC), you can put a card from this unit's Buddy Soul into drop to have it stay on the (RC)". [CONT]:During your opponent's turn's guard step, this card can be called to (GC) as a trigger unit, and it becomes a Grade 0/[Shield]15000 guardian.