Ways not to Defeat Cecil Dark Knight

[Fatal Impurity]

I would try and heal the D-Cecil, cause I thought that is what a true knight would do. But then I realized I just had to sit there and do nothing.

it just proves that us FF fans shouldnt try to be too clever and should just take a more literal approach lol

[Desert Merchant]

why do I not remember having to fight him? how exactly does this battle come about, is it optional? I'm sorry its been a long while since I have played but for some reason I dont remember a battle that was this hard.