When Khunkhuz, Tsar of Arms enters the battlefield create a colorless Equipment Firearm artifact token named Gun Emplacement with "When this enters the battlefield attach it to target creature you contol, Equipped creature has '{t}: Equipped creature deals 1 damage to up to any two different targets.'" and Equip {2}.

Whenever a creature dealt damage by a creature with a Firearm token attached to it, dies put a Revolt counter on Khunkhuz. If a Rebel creature died this way instead you may remove a Revolt counter.

At the beginning of your end step if Khunkhuz has 4 or more Revolt counters on him, exile and return him transformed.

Skulk

If Khunkhuz Zheleznyakov, Titleless deals combat damage to a player untap him.

{t}: Khunkhuz Zheleznyakov, Titleless deals 2 damage to any target; if that target is a Rebel creature he instead deals 3 damage.