I don't think tentacles fit well with what this guy has become over the course of all these revisions and rethinkings. Since he has no arms, I've come to think of the beast as a charger, barreling into battle, full-bore, smashing his opponent with his armor plates. Tentacles are cool, but there's no way he'd be able to generate any kind of speed with them.

Because his body is essentially a giant, heavy head, one could assume he'd require some thick, stocky legs to both support the weight and propel him into battle.