I'm sorry I must answer this way. Yes, I got suggestions – in the game – that Raelag was an elf first. One in the original campaign – Raelag was brought to being dark elf by Rite of True Nature. If Raelag's true nature was demonic, the rite would do nothing to him. Another hint was in a single scenario of Tribes of the East – I played Agrael, and one of Shadow Matriarch called said something like "Oh, it's you, Agrael… or should I call you Raelag?". Because of these hints, I believe Raelag was a dark elf first.