Crest Mark is a Weiß Schwarz card from Attack On Titan: Final Season AOT/SX04-063. Compare listings from Singapore Weiß Schwarz sellers on CardJio, then jio them on WhatsApp.
If you do not have a character with "Mikasa" in its card name, this card cannot be played from your hand. Look at up to X cards from the top of your deck, choose up to 1 card from among them, put it into your hand, and put the rest into your waiting room. X is equal to the number of 《Eldian》 or 《Corps》 characters you have +1.