Tsuki

Fluffy, "The Guardian" is a giant tiger that was fed the 'Batto Batto no Mi, Model: Vampire. This makes it so that one swipe of his claws could cause rapid aging, this is because the fruit steals peoples youth instead of sucking the blood out of them.

Personality
Fluffy is a very protective creature, not letting many people pass into the fountain unless they bring specific treats or defeat/distract him for long enough.