|Date of Birth||49 BE|
|Date of Death||Still alive.|
|Occupation||Pendulum Wars Veteran|
- "Do you know what (people) are mostly? Bastards. Bastard-coated bastards with bastard filling. But I don't find them half as annoying as I find naive bubble-headed optimists who walk around vomiting sunshine."
- — Dr. Cox, Scrubs
Field Lieutenant Bill Underbrook is a fifty-three-year-old Pendulum Wars veteran. He resides in Big Town with a number of other Stranded. He is a chainsmoker with a white beard and a green beret.
Bill came from a small town, Ritheno, which was also the home of the Matheson family. When the Locust attacked, Howie Matheson and his wife Angela had their third baby, Art, on the way, so Bill decided to help them get out safely. They left behind everyone else. They tried to reach the rest of Howie's family in a town called Olufti, but it had already been ransacked by the time they arrived. From there, they decided to travel to Ephyra.
Along the way, the second Matheson child, a girl named Eve, died of pneumonia. Bill thought himself the Mathesons' protector and has never forgiven himself for her death.
Upon reaching Ephyra, Bill and the Mathesons met Charlotte Edwards. They became good friends. Angela gave birth to her fourth child, Liam. The oldest child, Oliver, enlisted in the military and was killed not long afterward in an ambush. Deciding it was time to move on, Bill and the Mathesons bade their goodbyes to Lottie and set out for a new home. Eventually, they reached Pithodi, where they met Gabriel Sheridan and Aidan Foley. Bill and the Mathesons agreed to bolster Big Town's numbers and traveled back with them.
Everything was fine until Angela got pregnant again. She had a complete emotional breakdown and hanged herself with a leather belt because "she didn't want to bring any more children into (the) world". After that, Art ran away, and Howie vanished mentally and emotionally. Bill blames himself for not being able to protect them and vows to do better with the last Matheson, Liam.
For more on Bill today, visit Reconnoiter at FanFiction.net.