It's a Synchro that's practically meant to be a bridge towards his other Synchros, meaning on its own, it's not that threatening to game balance, especially when we don't have Red Daemon's Dragon and Scar-Red Nova Dragon yet anyway.
I could see Chaos King Archfiend and/or Exploder Dragonwing being drops, though they'd both also make sense as a Level 30 reward.
I agree with Multiple Piece Golem being a drop, though I'm assuming SR. I'd guess his Synchro, if any, would be UR. (If his UR isn't a Synchro, I'd guess Trap Eater before Multiple Piece.)