Bartholomew (バーソロミュー Bāsoromyū) was a person who served as a butler under the Formal Clan before his betrayal.
At first Bartholomew seemed to be a kind person, however under his mask is a selfish and lying man. He didn't want to reveal secrets to Mamina no matter what.
Bartholomew looks like an elderly man with short gray hair as well as matching gray shirt.
Bartholomew served the Formal Clan for a long time, it was revealed he leaked the seal and papers required for the ruined assassination attempt.
Bartholomew was involved in the House Formal frameup and is viciously beaten up by the house's girls in an attempt to force a confession to clear them and the would-be assassin. He resists where Bartholomew had continued to claim that he was innocent, but the JSDF stepped in and they were able to prove that Bartholomew was guilty as his fingerprints were found on the fake letter sent to Delilah. While Bartholomew continues to deny his crime the JSDF then used amobarbital in order to make the butler talk. It was later revealed that Bartholomew was a simple pawn and his reasons lies in the fact that he is in debt from enjoying women.
“I got rid of the person who tricked me!”
Deliah confirms to Itami that she killed him in volume 8, chapter 5 of the light novel
After the successful rescue operation of the last Japanese prisoner, Matsui Fuyuki, Deliah stated that she killed him for tricking her.