Does anyone have tips for this:

(SPOILER)I am fighting Cid in Draklor Labs and I am like lvl 37/38 Vaan, Fran and Balthier. So I tired a few times. I tried Quickening Chaining right away, I got like >10 chains and took half his life, but then to do more damage to Cid I had to kill his contraptions, meanwhile he had regent on him. So my second plan was kill those thing-a-ma-bobs then Quickening Chaining. Again I got like 10+ hits. Still I finally get him down and he goes beserk (literally) and slaughters everyone. By this time my reserve characters already died trying to revive my main (they are only level 12).

Anyways, does any have any tips for this battle?