Are you gonna use them at CQ or at farming, or just make them chilling at the back?

Voted Heracles myself.

My own one went to Demon King Nobunaga, should be useful later on since my Space Ishtar is find of sad in comparison. :)

Heracles because Bond CE, naturally.

That said, if it is for the Challenge Quest. 1000% Orion. That would be hilarious.

As for me, promise fulfilled.

ROMA!!!!

Herc's bond CE is vital, but in this case I'd recommend Super Orion if you're taking him to the CQ. Extra damage and bond and, I'm assuming once his NP train gains enough steam, enemy Orion's debuffs won't be an issue.