Kefka Palazzo:

If he is normally unbearable, Kefka is doubly unbearable being sick. Fortunately it doesn't happen very often. 

He hates being sick, feeling weak and having to endure the instructions of the people who offer to take care of him. He also feels terribly bored, his magic without responding in the same way to what it would do in full form... And nothing his carer do for him seems enough to make him feel better. 

Although Kefka carries many ills, derived from the infusions of magitek or a result of the side-effects, I would say that the greatest weakness he suffers would be in his stomach or digestive system. He has trouble digesting certain foods or amounts of food, especially those that are not natural or naturally made. (Often the texture, cooking or the spices used also influence)

Leo Cristophe:

He would act stubbornly, disregarding his bad condition, continuing with his daily tasks, until he had no choice but to go to the doctor and receive attention and rest.  

If taken care of by a friend or a family member, I imagine him being frankly grateful as well as a little embarrassed to occupy all the time of another person in his care. Without exceeding requests or demands when it comes to being taken care of. 

I don't have the impression that Leo has any  inclination that weakens his health more than the common ones or that complicate diseases... 

Terra Branford: 

She rarely gets sick, due to natural causes, by possessing magic in her body but in the case of being infected by something, she usually deals with the problem alone. Not only to not be bothersome, but because she knows that the recovery process is not as slow as that experienced in a normal human. 

Terra is very sensitive to temperature changes as a cause of her affinity with one element more than with others, in her growth less developed. Hence, Terra has some problems in contact with frozen objects or foods. The damage is not much, usually superficial as skin sores. 

Celes Chere: 

She will follow the instructions even reluctantly. Celes is a tough woman but she is also aware of when to stop and she will do so in order to be ready again. This is part of a character arising from military discipline and its responsibilities. 

Being careful, Celes is really shy, constantly showing appreciation and obedience.

Kefka could see the phoenix struggling, quickly weakening while it was attacked by Gestahl’s guards, magitek armour involved to help weaken its magic.

He was conflicted. He should let the little harpie die, he thought. He’d seen her talking to Leo and despite what his lover had said, he was still suspicious.

But…

A phoenix could be a powerful ally, or slave.

Kefka smiled at the thought, quickly jumping in and dispatching of the guards and armour, blowing it up and leaving the guards charred remains in its wake.

“Where did I come from?” he echoed, watching the weakening phoenix through narrowed eyes.

“The darkest depths of your soul.”

Kefka turned and immediately began casting a powerful spell, using his dark aura to reach to her and seep into her mind. He would take the phoenix as his own. It would make a powerful weapon.

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