Bill is an unwanted squatter hiding out in North Vegas Square. He has been squatting in the area for too long and has worn out his welcome with the locals. As the locals are distrustful of the NCR, the squatter will soon receive his comeuppance from Jules and Crandon.
If convinced to leave peacefully, Squatter Bill and his two squatter buddies will travel to the Casa Madrid Apartments in Westside, which they will occupy the rest of the game.
If the Courier kills Squatter Bill and the other two squatters that are with him, they will gain NCR infamy. If the Courier has a bad reputation with the NCR, this will cause them to attack on sight, making it impossible to deal with them peacefully.