Hardin build

Hardin on free summon! What luckkk. I think those IVs can simply be regarded as neutral, minus HP does not hurt as much as minus def or res considering that with his low speed he's going to get attacked twice anyway... Brazen def/res would work, it makes him super tanky in theory. If not I'm thinking of a crazy speed build with a speed bond A skill and hone armour (or some other speed support), and with vantage/guard/bold fighter as B skill. But that's a crazy build; the normal Brazen-Bold Fighter-QR seal build should work fine.

You might think his boon is bad, but 31 speed is workable.
You can go as easy as fury + aether. It's dual phase and Hardin should be able to heal in time.
Close def is also not bad, but might work better with vengeful fighter.
Sturdy stance might be easier to get.
Darting stance as seal works wonders for avoiding doubles.