Derek was a promising young recruit in the PEIA when the Resource Wars broke out in the 50s. He was my Chief Information Officer during the height of the conflict, and his elite hacking skills have pulled more than a few missions out of the dustbin. When the war ended the price on his head forced him underground. I had been buying intelligence from “Monst3r” for ages before realizing that it was Derek.
—Central

Derek Mossman, known as Monst3r, is a hacker, a freelance trader, and a former agent of the PEIA who joins Invisible for some special missions. He can also be selected at the start of the game.

In the game's story, Monst3r is an old friend of Central's, who offers to use his hacking skills to help Invisible evade and later seek revenge on the corporations who raided their headquarters at the start of the game. Additionally, he buys and sells items, weapons and augments to the agency.

Monst3r is voiced in the game by actor Michael Dobson.

Derek Mossman learned his trade the hard way, running petty info grafts as an orphan in post-industrial Manchester. Seeking access to the latest technologies, he wiped his own record and enlisted with the Pan-Euro Infosec Agency. He rose quickly through the ranks, joining the elite infiltration group run by Olivia Gladstone. Records after the war's end are spotty at best.

Inventory	Overclocked Neural DART
Augment	Fabricator Multithreading
Skill	Hacking 3
Age	46
Tagname	The Information Broker
Hometown	Manchester[1]
Years of service	0[2]

Derek Mossman was a skilled, self-taught hacker who stole and cheated his way out of post-industrial Manchester. His curiosity for exotic technologies far outstripped his means, and he originally joined the PEIA to gain access to the newest toys. Gladstone could see his potential and took him under her wing. Their fortunes at the agency raised together, and when Gladstone took charge she appointed him her second-in-command. While Derek is a serviceable agent, his true skills lay in logistics. His ability to produce credits and material seemingly out of thin air kept the PEIA fighting strong until the bitter end of the conflict. After the war, he would use those same skills to create one the most extensive private information gathering networks on the planet.

Derek is the Archive variation of Monst3r.

Inventory	Neural DART Transport Beacon
Augment	Particle Envelope
Skill	Hacking 2
Age	28
Tagname	Credit Monster
Hometown	Manchester[3]
Years of service	5[4]

Derek puts on an air of self-interest, but he's got more skin in this game than he's willing to admit. He saw the nasty side of corporate power as an orphan back in Manchester, and he's never forgotten it. He's able to put some of those feelings aside for the sake of business, but when the chips are really down he can still be counted upon. When I was captured, the agency wrote me off. I don't blame them - not many people walk out of a deprogramming chamber the same person they went in as. But Derek kept looking. He tracked down the facility where they were holding me, and was able to remotely hijack a nanofab within. A single neural disrupter in the right hands at the right time can make all the difference in the world.
—Central's assessment of Derek

Similar to how he acted in his youth, Monst3r affects the persona of a self-interested businessman. Despite this, he's willing to help Central and the Agency at a time when literally nobody else would, even putting himself personally at risk. Monst3r expresses his dislike of fieldwork multiple times and especially decries the transportation beam, though this doesn't stop him from joining Central in the final mission. He also expresses concern to Central, especially over Incognita, but is ignored.

Derek sounds completely materialistic and only interested in filling his pockets, but as Central's assessment points out, this shallow persona is very much an air he puts on. For better or worse, Derek was shaped by his early childhood experiences of growing up orphaned in Manchester amidst K&O “pacification” strikes. Despite his shallow airs, he has strong loyalty to Olivia and likely the cause of the PEIA as a whole.

Datalog

Neither Monst3r nor Derek have banter with other agents, although some is added in the Additional Banter mod.

At the start of a mission:

• “Information is power.”
• “Let's not take any chances.”
• “Their technology is quaint.”
• “God, I hate how that feels.”
• “Just point me at the consoles.”

When rescued:

• “Fancy meeting you here.”

Final words:

• “This is why I hate live operations.”
• “You want credits? I can get you credits.”
• “Could we not talk this over like adults?”
• “Operator, you better fix this.”

At the start of a mission:

• “Look at all this money. Let's take some of it.”
• “Alright, kiddies. It's time to go shopping.”
• “Take everything that isn't bolted to the floor.”
• “Ones are fine, but I prefer numbers with lots of zeroes.”

When rescued:

• “I really need to get a desk job.”

Final words:

• “You corporate bastards.”
• “This is not going according to plan.”
• “Everyone has a price, right? Name yours, and I'll double it.”
• “Money is power, but then so is that gun over there. Pity.”