Neil went to Black Mountain on Marcus's order to spy on Tabitha, an intelligent nightkin who had ousted Marcus as leader of the Black Mountain super mutant refuge. Neil's role is to divert other super mutants to Jacobstown, where they will be treated fairly. He has three distinctive scars located above his right eye.
Crazy, Crazy, Crazy: Neil tasks the Courier with overthrowing Tabitha from her rule. He can be persuaded (with 50 Speech) to aid the Courier by leading away the nightkin guarding Tabitha's broadcast station.
pcps3xbox360 When waiting to help you at the top of Black Mountain, Neil will give the response "whatever you do, be quick about it" no matter what you tell him. This is caused by the conditions for the "Let's go" response being unavailable if any of the Nightkin guards are dead, rather than if all of them are dead. [verified]
ps3 If you accept Neil's help but enter Black Mountain from the locked gate on the southwest side (by Tabitha's room) instead of going through the checkpoints, Neil will run around randomly when you approach him and cannot be spoken to. Waiting causes his map marker to move near the domes, but he is nowhere to be found. [verified]
pcxbox360 If you visit Black Mountain for the first time, Neil will wander off and can be sometimes found dead or under a rock when you visit later. [verified]
pcxbox360 Often, when he is talking, his mouth movements are out of sync or aren't moving at all. [verified]
xbox360 After meeting Neil near the crater of Black Mountain (had you passed the Speech check), he will either vanish, be glitched and get stuck, or get hung up on a rock behind him as he tries to run ahead. [verified]
pc Neil may be hostile when you meet him. Save your game before getting to the area and reload if he starts out hostile.[verification overdue]