Draggin wall wouldn’t do much good on him anyway with his Res.
He’s got special acceleration and a breath effect, so that screams ohko machine. He’s got good Atk for it, and can fire off Luna or DA instantly after taking a single hit.
DC lends to him taking ranged threats, but again with mediocre Res he can probably be ohko’s even through that first hit DR. I’d go with any Unity or Ideal instead to boost his Atk as much as possible with little effort. 2nd to those would be a bond 4 since he’s likely going to be near allies anyway.
B slot: lull Atk/Res. Ensure that the foe can’t buff their way out of him doing massive damage. 2nd to that would be lull Spd/Res so he has a better chance at doubling or preventing a double if need be.
C slot: JDA. Or big brain it with TP so he can run dragon fang or Astra.
Seal: anything Atk boosting like a solo or form. Just make sure it lines up with his A slot.