Enter Mega Gengar EX , a Darkness type instead of Gengar EXs Psychic typing, and taking the shenanigans to another step by preventing all Trainers from being used
The companion mechanic allows you to add a companion to your sideboard and reveal it if your starting deck meets the conditions printed on the card
The reason behind its infamy is its attack Night March, which, for the simple cost of 1DCE, is able to deliver insane damage on just the first turn
Its first ability can have a lot of applications, allowing you to both tap down your opponents permanents and untap yours
Master Duel is here and with it a ton of decks to build and play with
Its the basic gameplan most go-wide decks employ: Make an army, then make the army lethal