In all honesty, nobody really knows. None of the games have ever shown a clear human form for him, nor has he ever been seen without his helmet (assuming it can be removed like Cyrax's). There's also virtually no story about him before he volunteered to become a cyborg. It's entirely possible he is Japanese though, as there really isn't anything pointing to the contrary.

1. Teku means metal. Particularly iron. Tekken...King of the Iron Fist...obvious.

2. since Sub-Zero is of mixed amero-asian descent, Sektor could be anything.