Engineer B (技術者Ｂ Gijutsu-sha Bī) is a character in the Yu-Gi-Oh! anime. He works in KaibaCorp's research and development department. The name "Engineer B" is used in the ending credits and in reference sheets.
Engineer A, Engineer B, and Mokuba Kaiba occupied the control room while Seto Kaiba tested the second generation Duel Disk and the power of "Obelisk the Tormentor" against the Duel Robot. Engineer B set the robot's tactics level to max and turned on the computer's Auto Duel System. During the Duel, the robot Summoned "Blue-Eyes Ultimate Dragon" and Engineer B began to worry about Kaiba's safety, noting that if Kaiba were to be attacked he would suffer physical damage, per the Duel Disk's configuration. Kaiba raised the ATK of "Obelisk the Tormentor", using its effect. Engineer B said that the rapid increase was big trouble, as the machine's became overloaded and the computer in front of him blew up.