Activate Ashnod's Altar by sacrificing Accomplished Automaton, adding {C}{C}.
When Accomplished Automaton dies, Nim Deathmantle triggers, causing you to pay {4} to return Accomplished Automaton from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Accomplished Automaton enters the battlefield, its fabricate ability triggers, creating a 1/1 Servo artifact creature token.
Activate Ashnod's Altar by sacrificing the Servo, adding {C}{C}.
Repeat.

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Nim Deathmantle

Ashnod's Altar

Accomplished Automaton

Activate Krark-Clan Ironworks by sacrificing Accomplished Automaton, adding {C}{C}.
When Accomplished Automaton dies, Nim Deathmantle triggers, causing you to pay {4} to return Accomplished Automaton from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Accomplished Automaton enters the battlefield, its fabricate ability triggers, creating a 1/1 Servo artifact creature token.
Activate Krark-Clan Ironworks by sacrificing the Servo, adding {C}{C}.
Repeat.

Combos with "Accomplished Automaton"