He was pretty easy. It's just time consuming. All I did was constantly spam slow, bleed, and gross out the armed service men (weapon attachments). The unarmed serviceman is easy to counter. Spam ranged attacks on him. Keep butters handy for healing, and use stan as the muscle. Took me about 45 minutes to beat him.
Yea, this battle sucked, took me a few tries. Main thing to me was making sure to not only fully block his first status inducing attack, but a couple rounds later when one of the SS tosses the concussion grenade. Being a thief and being able to stack t he bloddy effect on them all though won the battle for me in the end.