A sort of holdover from Matsumoto-sensei's previous work, Pochikuro, is Kikoru's butler, Sebas. (瀬羽須 in Kaiju No. 8. Full name in PochiKuro was セバスニャン/Sebasnyan.) "Sebas" comes from Sebastian, which is the manga/anime equiv to "Jeeves" for butler names. (1/2)
