When Lightning Crafter enters the battlefield, its champion ability triggers.
Holding priority, activate Kiki-Jiki by tapping it, creating a token copy of Lightning Crafter with haste.
When the token Lightning Crafter enters the battlefield, its champion ability triggers, exiling Kiki-Jiki.
Activate the token Lightning Crafter by tapping it, dealing 3 damage to any target.
Activate Umbral Collar Zealot by sacrificing the token Lightning Crafter.
When the token Lightning Crafter leaves the battlefield, it triggers, returning Kiki-Jiki from exile to the battlefield.
Resolve the Umbral Collar Zealot ability.
Repeat from step 3.
This loop turns Lightning Crafter and Kiki-Jiki, Mirror Breaker into a self-sustaining cycle of fiery destruction by using their triggered abilities to keep each other safe and active. When the token copy of Lightning Crafter enters, its champion ability exiles Kiki-Jiki, but tapping the token for 3 damage and feeding it to Umbral Collar Zealot's sacrifice outlet immediately returns Kiki-Jiki to the battlefield. Because Umbral Collar Zealot also triggers a surveil with every sacrifice, you can easily filter your draws while dealing infinite damage to any target.