Indigo

 Dr. Indigo (Dr. インディゴ) is an ingenious member of Shiki's crew. He is the one that created Boss and the other monstrous animals under Shiki's dominion.

Appearance
Indigo is an indigo haired doctor with a mime-like appearance. He wears a large yellow polka dotted indigo scarf and indigo-striped shoes that make a farting noise every time he takes a step. He also wears indigo overalls and a lab coat over them.

Personality
Indigo is a doctor with an eccentric personality. He has a distinct laugh which goes "Piro piro piro". He adorns shoes that emit sounds of flatulence whenever walking. He also often tries to act like a mime, but often breaks character by suddenly talking.

Shiki
Indigo shares a rather humorous relationship with his captain Shiki. Whenever Shiki says or does something stupid, Indigo acts as a straight man and slaps him. After which they both present themselves to others like a typical comedy duo after a joke. Regardless, he is loyal to Shiki and spent twenty years creating super-powered creatures in Merveille for the Golden Lion Pirates to take over the world.

Abilities and Powers
Indigo is a chemist of sorts. He was the one in charge in the development of Shiki's scheme involving all the monstrous animals. He may be a strong fighter who uses scientific materials since he was seen along Shiki and his crew when they fought against Gol D. Roger and his crew. He may also have some skill with a sword as he was seen attacking Luffy with it in one scene but it was never seen again.

Chemical Juggling
He has the ability to produce explosive chemicals from his body and attack with them, called Chemical Juggling, still it is unknown if it is the ability of a Devil Fruit or the effect of some chemical he uses in battle, he uses his ability to create chemical orbs and arrange them above him and shoot them from his hand, and create a large orb with a much more explosive effect. The way he manipulates the chemicals ressembles to the skill of Juggling.

Trivia

 * Of Shiki's main crew members, they all have a color in their name.
 * The reason his scarf is always hovering behind him (as if wind was blowing through it) is because there is a wire inside the scarf.