After Jesus' arrest:
15 And Simon Peter followed Jesus, and so did another disciple: that disciple was known unto the high priest, and went in with Jesus into the palace of the high priest.
16 But Peter stood at the door without. Then went out that other disciple, which was known unto the high priest, and spake unto her that kept the door, and brought in Peter.
The 3rd-person reference has led numerous commentators to conclude that the "other disciple" and the "disciple whom Jesus loved" are one and the the same (for example, this was the view of Jerome--see Clarke's commentary).
But other possibilities have been proposed as well. I've seen suggestions ranging everywhere from Mary Magdalene to Judas Iscariot.
This question is not asking who the "disciple whom Jesus loved is", though you are welcome to suggest they are the same person if that is your view--but please explain why. My question is who is the "other disciple", and whether or not his being known to the high priest tells us anything about him?
(Note: I'm referring to the disciple as a man because μαθητὴς in this passage is masculine--but feel free to argue otherwise if you believe that interpretation is unwarranted)