Nitro Mechanoid

Action - Banish a card from under Nitro Mechanoid: Attack

Overpower

Temper

Rulings

From the Dynasty release notes

If Construct Nitro Mechanoid does not transform ALL of the Mechanologist head, chest, arms, legs, weapon and 3 Hyper Drivers that are targeted, it negates itself and all of the targets remain unchanged.
The cards that are transformed this way go underneath Nitro Mechanoid. They are not considered to be in the arena, and their abilities are not functional unless they specify otherwise.
If there are no cards beneath Nitro Mechanoid, it can not attack using its activated ability.
If an opponent takes control of Nitro Mechanoid, cards underneath Nitro Mechanoid remain underneath the card. If the cards that are banished to attack, they are banished to their owner’s banished zone

Keyword notes

Overpower - The defending hero can’t defend this with more than one action card.

Overpower is a static ability that generates a continuous effect.
A player can not declare more than one defending action card against an attack with overpower.
Overpower does not prevent additional action cards being added as defending cards through effects (e.g. Amulet of Havencall).

All keywords

Temper - Temper is a new keyword that exists on equipment in Crucible of War. Usually high in defense, Temper equipment presents a choice when it is down to 1{d}, of whether to defend with it one last time and see it destroyed, or save it to use for its ability.