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.

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Nim Deathmantle

Krark-Clan Ironworks

Accomplished Automaton

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.

Ashnod's Altar

Activate Viscera Seer by sacrificing Accomplished Automaton.
When Accomplished Automaton dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Accomplished Automaton enters, its fabricate ability triggers, putting a +1/+1 counter on it.
Resolve the Viscera Seer ability.
Repeat.

Combos with "Accomplished Automaton"