Karn, Legacy Reforged's power and toughness are each equal to the greatest mana value among artifacts you control.
At the beginning of your upkeep, add C for each artifact you control. This mana can't be spent to cast nonartifact spells. Until end of turn, you don't lose this mana as steps and phases end.
![Karn, Legacy Reforged (Foil Etched) [March of the Machine: The Aftermath]](http://paradoxtcg.com/cdn/shop/products/6b36231c-f7cf-5967-bd6c-d0304f7347d2.jpg?v=1702309875&width=1445)
