Helm of Chatzuk [Unlimited Edition] WTR042-C Evoke {2}{U} (You may cast

Evoke {2}{U} (You may cast this spell for its evoke cost

Iroas isn't a creature

When Illusions of Grandeur leaves the battlefield

it's an artifact creature with power and toughness each equal to its converted mana cost

Helm of Chatzuk [Unlimited Edition] WTR042-C Evoke {2}{U} (You may castSet: Unlimited Edition Type: Artifact Rarity: Rare Cost: {1} {1}, {T}: Target creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)