The Last Guardian

Effect

[Main] Reveal the top 3 cards of your deck. Add 1 [Cool Boy] and 1 card with the [Royal Knight] or [X Antibody] trait among them to the hand. Return the rest to the bottom of the deck. Then, place this card in the battle area. [All Turns] When any of your Digimon with [Omnimon] in its name would leave the battle area, ＜Delay＞ (By trashing this card after the placing turn, activate the effect below.) ・1 of those Digimon doesn't leave.

Source Effect

Security Effect [Security] You may play 1 [Omekamon] or [Cool Boy] from your hand or trash without paying the cost. Then, place this card in the battle area.