Khameleon

Khameleon is an alien, master of disguise. Black was hired to assassinate him for stealing secrets from a galactic mafia. He appears in Chapters 148 to 151.

Ability
His machine allows him to transform in another person.

Plot
Khameleon was trying to escape from a space mafia with highly classified information. So, the mafia hired the assassin Black to kill him.

Khameleon hide on the Earth where he replace Arashiyama, butler of Tenjōin Family Mansion, and he welcomes Saki' friend group she invited. Howewer Black found and shot him. So, Khameleon fake his death. Knowing that he had no chance against Black, he replace Saruyama to use the princesses of Deviluke (Lala, Momo and Nana) and Golden Darkness to defeat the assassin.

Indeed Black almost attack them, but Yami (not fooled from the fake death) reveal Khameleon' identity to all and damage his machine. Khameleon try to escape and turns into Nana hoping to confuse them. However, due of the machine' damages, his transformation backfires as he don't copy Nana's chest size (making a busty version of her) which angers the girl into beating him to a pulp. Yami convince Black to don't kill him and Zastin hand Khameleon over the galactic police.

Trivia

 * Khameleon' appearance is based on King Nikochan, a character from the manga and anime Doctor Slump.