yugioh master duel stall deck Ultimate Top 12 Best Stall Cards

He's able to capitalize on having other units in play, but true to his reputation as a singular force of destruction, can also enable the casting of all but the strongest or most expensive spells with little additional support in one fell combat step

That made good answers hard to come by while the Sliver deck was functioning as intended, as winning combats was hard, winning them quickly without trample was even harder, and removal was temporary

Kasmina had encouraged the twins to apply

Roaring Moon ex fixes that by being a powerful attacker that can oneshot any Pokmon on the first turn (even something like Arceus & Dialga & Palkia-GX)