Maestro de eterium

Master of Etherium

Master of Etherium's power and toughness are each equal to the number of artifacts you control.
Other artifact creatures you control get +1/+1.

"Only a mind unfettered with the concerns of the flesh can see the world as it truly is."

March of the Machine Commander

The Brothers' War Commander

Neon Dynasty Commander

Double Masters

Commander 2016

As long as Master of Etherium is on the battlefield, its ability will count itself.

Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to Master of Etherium may become lethal if other artifacts you control leave the battlefield during that turn, and damage dealt to other artifact creatures you control may become lethal if Master of Etherium leaves the battlefield during that turn.

The ability that defines Master of Etherium's power and toughness applies in all zones, not just the battlefield.