Nyx

Nyx is a first generation titan created by the Old Ones in order to alongside Hades be the Godess of the Underworld a role that she held until her death during the events of the Eternity War.

Execution
Tartarus would following the escape of much of the rebel titans from Olympus remain behind unwilling to leave following the rejection of his father Hades and thus unwilling to submit or leave he begin taunting Zeus leading to his execution.