+atk -def dorcas or + res - def dorcas

+ atk better than + res...

Maybe attack, but with his already hight attack, QR, and more resistance, you could tank mages...

+RES actually helps since he is a Distant Counter unit. I can never understand why no one likes Resistance on a DC unit as that's what they're used for. His neutral Attack is 51 with the Tomahawk, making him a Green Ike with more Resistance. Plus, he gains 4 points of Resistance rather than 3.

+ATK does let him reach 54 attack and allowing him to deal a lot of damage, especially if you keep Fierce Stance. Mine is +ATK -SPD, and can vouch for his potency.

Whichever you choose is up to you.