Hp: approx 500
Weaknesses: Fire, Holy and Lich
Ramza: any job will do.
Agrias: Only if she has Lighting Stab, otherwise she won't be much help.
The other three should either be Skeletons, Bone Snatches or Living Bones. Make sure they have over 100 hp.
Queklain will start off by using Nightmare, the effects are usually Death Sentence or Sleep. He also might use Bio, Bio2 and Bio3, which aren't too strong. Have Ramza attack, while Agrias use Lightning Stab, the 3 undeads should use their distant attacks or take him head on. Now why undeads ? If Queklain uses Nightmare on them, and they get Death Sentence, the joke's on him, since it will not affect them because they are already dead. So this gives you a small advantage over him. I do not reccomend mages here since he'll easily reach and kill them while they are still charging. Also, your levels should be 20 + and you shouldn't have too much probs.