Dier is a young genius Doll technician and a long time collaborator of Squad 404. He is also the younger brother of Sier. While he's a background character in the main story, he makes a memorable appearance as a main character in the Bounty Feast event under the identity of Dima. At some point, Dier hired SMG UMP45 and SMG UMP9 to combat a Dolls kidnapping gang in his home city. 45 and 9 ended up helping HK416 and an abandoned maid Doll against two of the kidnappers, and with the help of 416's high combat specs, they neutralized 18 thugs in their own base and let the police pick them up, with Dier's anonymous manifesto against police corruption later being shared in the news. After 416 accepted to take care of the Doll she had saved, she asked Dier to make her a T-Doll. Being the same model as the maid Dolls in his parents' mansion, and the same model as the first Doll he had ever worked on, Dier upgraded her as best he could and outfitted her with a custom fire control core and a weapon from his personal collection, christening her AR G11. However, he had to make several tweaks before her neural cloud stopped crashing intermittently from the load of her advanced fire control core. Dier is the son of a rich family and a self-proclaimed genius in Dolls engineering, calling himself the “Almighty Mechanic”. He is one of the rare Dolls technicians capable of disabling the core order preventing Dolls to attack a human being. Dier treats his repair work as restoring an art piece by being minimally invasive and destructive, he believes that Dolls have a right to dignity and that traffickers who kidnap, dismantle and resell Dolls after wiping out their memories are a disgrace to his line of work. Sier is Dier's older sister, and considering his poor accounting skills he mused about making a Doll replica of her, since his sister was occupied with her own business. Sier later worked as Dier's accountant while also doing the tasks Dier shouldn't, such as handling female Dolls clothing. Sier care about and sometimes impart tough love on her younger brother, but when asked about their radically different hair color, Sier hints that there is more to the sibling's past than it appears. Dier is the main technician of Squad 404 and performs maintenance, repairs and upgrades on their neural clouds and bodies in his own workshop at his parent's mansion, or in underground workshops near the squad's areas of operation. He also provides remote tech support in emergencies. While getting handsome rewards for his work, Dier is regularly bullied into underselling his work by 404, especially by 45. Since he could easily get by with his normal line of work as a Doll technician, 404 is a kind of passion project for Dier. 404 suspects Dier to find a salacious interest in working with Dolls, and though he always denies it, his fascination with maids sometimes get the best of him. Both Dier, Sier and their maids enjoy video games. Dier can be selected as an adjutant on the main menu, but some dialogues indicate that he is the original and others that he is an A-Doll he created in his own image. It is worth pointing out that Dier and the Commander don't know each other in the core stories, so like other NPC adjutants besides Kalina, this adjutant's existence shouldn't be considered canon. Dier started playing The Division, roleplaying as a female character called Dima and using a neural cloud backup of 416 as an ally, called AR Agent 416. After being derided by Agent 416 for being bad at the game, Dier tried to tweak her character to make her friendlier but caused it to integrate with the game's data, turning her into Fang, a new boss affiliated with the Last Man Battalion. The bug also turned on the safe mode of Dier's VR headset, which would cause it to lose all of his game data if he tried to forcefully disconnect. The only way to exit safe mode would be to delete Fang's data by killing her in the game, which Dier couldn't do by himself. After he found out how to send messages on the internet from the game, Dier contacted two T-Dolls to join and help him take out Fang. Embarrassed to be found roleplaying a female character, Dier passed Dima as an NPC, but they still couldn't beat Fang. The two Dolls, AR RFB and AR MDR, took to Grifchan and advertised a tournament with a fake 10 million dollars cash prize to recruit more players and beat the game. From the unexpected newcomers, Dier copied AR Vector's data as the most efficient player to create a new ally called AR Agent Vector, but the copy was corrupted by Fang and became Hellfire, aligned with the Cleaners, creating a second boss to destroy. When Dier broke character as the end of the tournament approached, the real 416 recognized him, and after her and Vector defeated their alter egos and remained as the last survivors, they forced Dier to reveal the truth. Dier explained and pleaded to the two Dolls not to reveal he had been “cross-dressing”, but he didn't know that the tournament was being broadcast to Griffin's base, provoking general hilarity among the Dolls, pity from the Commander, disgust from G11 and UMP9, and unspeakable fury from UMP45 who immediately set out to beat him up. 416 eventually offed Dima with a bullet to the head after learning there was no real cash prize for the tournament. Sier sent a formal letter of apology to the Griffin base the day after. In his adjutant dialogues, Dier laments that his humiliation gave him trust issues and that he could have avoided it if the Commander had taken part in the game. He also reports that the Dolls dedicated a restroom to Dima to bully him. -IOP Wiki