It’s called Islam, that’s what drove him, the islam 101 variant.
What turned Tom from High Wycombe into a throat-slitting jihadi called the White Beast?

Beset by the tribulations of youth, Thomas Evans – killed fighting for al-Shabaab – confounded his family not by dropping out to become hippies, or joining some anti-Establishment protest group, as troubled teenagers might have done in times past, but by converting to the Islamic faith. According to High Wycombe’s Muslim community leaders, it is an option that is becoming increasingly attractive to disillusioned young whites.