If your opponent tries to be clever by not attacking you after Step 1 (leaving your Radiant Steelix in the Active Spot and you possibly in a position to deck out), you can instead use Banette to get the new Sword & ShieldLost Origin Supporter Step 3: This is the most difficult part
If a Ritual Monster you control attacks a Defense Position monster, inflict piercing battle damage to your opponent
Two powerful attacks in Psychic Sphere (50 damage) and Psydrive (150 damage) mean Mewtwo can take out pretty much any Pokmon in the game
Officially licensed, with 197 total cards across 14 rarity tiers, perfect for trading, display, and gameplay
Late in the game aim to digivolve into [EX10-036 Magneticdramon] then repeat the deletion effect and security trashing effect to bring the battle to an end
You also need to untap with your commander and eight mana, and there are many expensive spells that will do something akin to ending the game in a five-color deck if you resolve them