Cetinkaya, 33, has a full beard and has been praying to Allah five times a day ever since he found himself, as he says. He’s the son of Turks from Mardin, a city on the Syrian border. He speaks fluent Arabic and doesn’t need a German imam or YouTube videos to understand what God wants from him.

God wants Cetinkaya to devote himself to “jihad.” But jihad is really just the Arab word for struggle, the struggle one endures while on the path to Allah. In the Koran, the “great jihad” is not the fight against non-believers, but each individual’s struggle against himself, against his own weaknesses, and against the evil that resides in every human being.

Cetinkaya is a successful fighter — in his struggle against himself, and against others he encounters in tournaments. In his sport of choice, Mixed Martial Arts, the combatants fight each other in a cage. It has its origins among the ancient Greeks, who called it Pankration. Even Socrates was a practitioner of Pankration, a full contact sport in which the combatants wrestled, boxed and kicked each other.

Cetinkaya is a popular trainer who runs his own martial arts school. When he walks through the streets of Hamburg, young men point at him or shake his hand. They tell him that they hope to be fighters like him one day. They have respect for Cetinkaya, who is a good fighter and a devout Muslim, a role model who dispenses advice.