Optiman was native of earth-36 and one of the analogs of Superman through the multiverse. In his world his role was similar to the last son of Krypton, as the leader and inspiration for the super team Justice-9. He also was recruited by Captain Marvel as member of the Supermen of the Multiverse against Mandrakk. However he was no match to Superdoom, a thought robot from earth-45, who killed him, depiste the help of the other heroes.
However that was not the last time than Optiman would appear. He returned as a gentrified zombie to haunt his former teamates as part of the Gentry attack. Apparentely however, the menace was halted and now Optiman again rest in peace.
As the rest of the natives of earth-36, Optiman is a homage/parody to Bigbang's Ultiman who is indeed a homage/parody to Superman himself.