As far as I know, yes. After defeating Emet-Selch, Elidibus is the last unsundered Ascian. That is, an Ancient whose soul wasn't split between the shards. However, his essence is stuck in the Crystal Tower after we defeat him. Then, we kick Fandaniel's Zodiark butt to smithereens, leaving Elidibus, or at least his essence, as the last Ascian alive. But he fades as soon as he transports the Warrior of Light to the past.