B6-21 is a synth mentioned in Fallout 4.
Background
B6-21 works for the Institute, and was formerly stationed at Site Alpha as a member of group G3376. They, alongside H7-44, and K0-84, were recalled, leaving C8-65 as the sole member of group G3376 left at Site Alpha.[1]
Appearances
B6-21 is mentioned in Fallout 4.