in its mana cost, X is 0 for the purpose of determining its mana value.Tezzeret, Cruel Captain gives artifact decks a planeswalker that gains loyalty whenever your artifacts enter. His zero ability untaps an artifact or creature, adding a +1/+1 counter if the target is an artifact creature. His minus-three ability searches for an artifact with mana value one or less, making him both a resource engine and a way to find a specific inexpensive tool.
Sol Ring and Skullclamp are practical search targets with very different roles. Untapping a mana artifact can help finance the rest of your turn, while untapping Steel Overseer provides another opportunity to grow an artifact creature army. Treasure and other artifact tokens also add loyalty when they enter, allowing a token-producing artifact deck to support the loyalty costs naturally.
The tutor puts the artifact into your hand rather than directly onto the battlefield, so keep enough mana available to deploy what you find. His untap ability also needs a legal target, and the counter bonus applies only if that target is both an artifact and a creature. These details help determine whether an activation produces immediate value or merely prepares a later turn.
The emblem can eventually turn an artifact into a growing creature threat, but Tezzeret should earn his slot through the earlier abilities. A deck with frequent artifact entries can repeatedly recover loyalty while using the tutor or untap mode. Keep blockers or interaction available so opposing attacks do not remove him before that recurring value develops.
