well I'm not sure how to kill it but I think it's best to data drain it because I heard sum1 said that you get a really good twin blade weapon like the best in infection.
I killed it with Blackrose and Piros(recommended party by friend...took me a lot of nagging from them to use him) and just made them attack while I ran around healing. Don't try magic I found out that does pretty much NOTHING to it. Bring a good amount of resurrects, healing potions and health drinks cause it had this one fire breathing attack that's strong. Oh and restoratives cause it also causes confusion. It doesn't have other attacks other than the fire breath and confusion spell I think. I beat it around level 34 or something I think. Not sure how much EXP you can get since I just data drained it. It's not a big toughy as long as you keep your two attacking characters alive. As long as Kite stays far enough not to get hit but to use items and heal he won't get hurt at all. Well for me he didn't get hit. I suggest you bring two characters who have a high attack.
definetly data drain it you get a hyakkidorann stats are very high for infection and if you dont data drain it depending on your level you get 100 exp or so