One of Many Faces, Illyasviel (FS/S64-E084S SR) [Fate/Stay Night [Heaven's Feel]]

[CONT] During your opponent's turn, all of your other characters get +500 power. [ACT] Brainstorm [(1) [REST] 2 of your characters] Flip over 4 cards from the top of your deck, and put them into your waiting room. For each climax revealed among those cards, search your deck for up to 1 blue character or character with "Shirou" in its card name, reveal it to your opponent, put it into your hand, and shuffle your deck.