Catar-Ol is one of Carter Hall reincarnation who lived on the planet Krypton; he was a teacher to Kara and together they created a portrait showing Krypton’s history. On the eve of Krypton’s destruction Carter traveled back in time to meet Catar-Ol in order to retrieve a weapon capable of defeating the Deathbringers.
Catar-Ol was summoned with the rest of Hawkman’s reincarnation in Carter final confrontation with the Deathbringers.