"He .. an Islamist poising as Mahdi"
?? eh? The Mahdi is translates to the Messiah.
In Sunni Islam, Hanafi school of thought, for which Erdogan subscribes to, the Mahdi is Jesus resurrected. They believe Jesus never died on the cross, that God replaced the body with a fake and raised Jesus to Heaven, to return at a later date to Sheppard in the End days.
Erdogan is scum and a tyrant for sure, but if he claimed himself Jesus, he'd be labeled and apostate and people would be out for his head.