He is known as ruthless, arrogant, and aggressive businessman who uses questionably legal tactics to get what he wants. His usual weapon is a gun.
The Fall of Shiganshina Arc
On the day of the fall of Shiganshina in year 845, he is seen at Trost District discussing with other men the news about the breach on Shiganshina, and wondering if Wall Maria has fallen or only the outer district was lost. They are then approached by a Garrison member who informs them that the inner gate was destroyed too and thus Wall Maria has effectively fallen. This is an anime-only scene.
The Battle for Trost Arc
During the Battle of Trost, Dimo is seen holding up a line so he can escort his merchandise out of the city, disregarding everyone else. Dimo blocks the inner gate of Wall Rose with his cart, effectively preventing most of the survivors from escaping the town and causing more death risk for the Garrison and new graduates soldiers. Despite the pleas and angry protests of constant people, Dimo states that he owns the companies in Trost and pays for everyone's meals, thus his merchandise is worth more than all of them. He trys to convince the citizens to help him with the promise of a reward. Mikasa Ackerman notices the situation and tells Reeves that her comrades are dying trying to buy time for the citizens to evacuate, but he simply responds that it is natural for soldiers to die for the sake of protecting people. He's only stopped after Mikasa Ackerman beat up his bodyguards and threatens him to let the people in or she will kill him. Dimo reluctantly agreed.
After the Battle
After the Trost is rid of the Titans, Dimo becomes the most hated person in Trost and an outcast. However, the royal government and the Military Police Brigade abandon Trost to its fate after the great battle, leaving the population and the Garrison on their own. Trost is given for doomed anyway and the people in power believe that the city will fall sooner or later. Although he hates this, believing in selfishness, Dimo knows he has money and power to save his city and can't let the people suffer and starve. He uses his position to save Trost, supporting the Garrison and giving people jobs, selling merchandise, and helping to rebuild the buildings. All that, despite he was made an outcast by the entire Trost.
The Uprising Arc
The false invasion of Wall Rose by the Beast Titan and the escape of the infiltrators identities of the Colossal Titan and Armored Titan back to their homeland bring the kingdom in chaos, riot, and fear; order starts falling in the Wall. A civil war is provoked by the infamous assassination of Minister Nick, the wealthy powerful pastor of the Church of the Walls. The culprits, who are the King and the Central Military Police Brigade, officially blame the Survey Corps for his death and since everyone saw Levi and Hange Zoë escorting the priest, they believe it and the government puts a bounty on every Survey Corps member, as they are considered rebels and enemy of the King, forcing them to disappear and hide. The people blame Erwin Smith for their woes. As Nile Dok enforces the propaganda of the Walls, Dimo Reevs locates the position of Eren Yeager and Historia Reiss who wanted by the King.
Dimo uses the angry starving mob of Trost attacking Levi and the Special Operation Squad. Dimo's subordinates kidnap Eren and Historia, with the intention to deliver them to the Military Police. But Dimo and his men are pursued by Levi's squad, who also had sent Eren and Historia to hide in the countryside. Unaware of this Dimo and his men have Jean Kirstein disguised as Eren and Armin Arlert crossdressed as Historia in a deposit of the Reeves Corporation. As Armin is being sexually molested by one of Reeves'men, Levi and his squad ambush Dimo's group and manage to capture him. Dimo takes out his gun and tries to shoot Mikasa, who recognized him. Dimo surrenders and compliments Levi and Mikasa's abilities, as he respects strong people who fight. Dimo and Levi have a talk in which Dimo admits that he has been commanded by the Military Police to kidnap Eren and Historia or else his wife and children would die with him. If Dimo doesn't deliver them in the estabilished day, he will suffer the consequences. Levi convinces Dimo that the government will never save Trost and its people, even if Dimo helps them. Instead Levi explains that the Survey Corps, now hated outcasts abandoned by the government, need provisions, money, and support to survive, or else when Bertholdt and Reiner attack again with the Titans, humanity will be already doomed (still unaware of Rod knowing everything about the outside world and the Titan's powers). Levi offers Dimo support to protect Trost and his family if he helps the Survey Corps with their plans and give them financial support. Dimo and Levi get along and strike a deal.
Following Levi's plan, Dimo pretends to work for the government and do as he was instructed by the Central Police. He meets the actual murderers of Pastor Nick, Djel Sannes and Ralph, and carrys them in a cart. Dimo rides the cart, telling them he is taking them to the place where he has Eren and Historia captured, but purposely throws the cart down a cliff. As Sannes and Ralph fall into the river down below, they are rescued and captured by Survey Corps and later they are questioned by Hange, Levi, and Moblit.
When the day of delivering Eren and Historia to the Military Police finally comes, Dimo and his son Flegel stay with Levi, Eren, Historia, Jean, Armin, Mikasa, Sasha, and Connie in the hideout of the squad. Dimo apologizes for Flegel acting like a spoiled brat, as he made rude demands to Levi. Nifa explains the plan to Dimo, Eren, and Historia.
Dimo and Flegel bring Eren and Historia to a cave. Previously, Historia and Levi had a discussion that ended with Levi physically attacking Historia and threatening her to become the future queen, whatever she wants it or not. Flegel inquires as to why he and his father are going along with Levi's plan, saying that he would have beaten Levi up if he had raised his hand against Historia for any longer. After Dimo explains why he trusts Levi, Flegel calmly goes to outside to urinate. Dimo assures Historia and laughs as he tells her that once she become queen she will able to hit Levi without having him react. Eren laughs about it and agrees. Captain Kenny Ackerman, the murderer of Historia's mother and Levi's uncle (and Mikasa's relative), arrives with Traute Carven and other of his men. Dimo and Flegel meet them away from Levi and the others, bringing only Eren and Historia with them. Dimo shows Kenny Eren and Historia (this time really them). However, Kenny knows everything about Dimo's betrayal and how he delivered 2 of his men to the Survey Corps. Kenny asks Dimo if he knows about a man known as Levi Ackerman and Dimo assumes he is talking about Captain Levi. Dimo is then killed by the Captain by having his throat slit open. Flegel survives and hides in tears until Kenny and the other cops disappear with Eren and Historia. The plan fails and no one is able to follow Eren and Historia with Kenny to their location. With this, the government orders the immediate deaths of every single hidden Survey Corps member.
Flegel disappears and Dimo's body is taken to Trost District by the Military Police who blame the death on Erwin Smith and the Survey Corps. Dimo's wife and daughter are sobbing on the ground next to him and his wife tells Erwin to get away from her husband. Erwin begins to talk about the bad things Reeves' did like blocking the evacuation from Trost and using questionably legal tactics. However, he then talked about how Reeves had saved Trost even though the citizens made him an outcast. Erwin then promised to avenge his death.
Later, Hange and Moblit find Flegel running in the alleys of Trost from the Military Police, who are trying to murder him. Flegel asked the policemen why his father was killed. Although the leading policeman is confused as to why Flegel is asking questions at a time like this, he explains how Dimo betrayed the MP, insulting him in the process. Hearing this, Flegel adamantly states that the policeman does not understand anything, and that he chooses to have faith in the people that his father believed in. The policeman, angered by Flegel's words, yells that he should be begging for mercy like a pig, to which Flegel replies by telling him to look above.
Hange and Moblit knock out the policemen and save Flegel's life. Many of the citizens in Trost emerge from the building, one of them saying that they have heard the truth about Dimo Reeves' death and all of them will attest to it. The policeman shouts at the crowd, threatening them and claiming that the news of the incident will not spread for more than three days, but is stopped by Flegel, who sits on his head. He vows to protect Trost and announces himself as the new CEO of the Reeves Company, much to the happiness of the citizens.
After the defeat and death of Rod Reiss in his 120m abnormal Titan form, Historia Reiss is crowned as the queen of the Walls and the Reeves Corporation supports the upcoming expedition to retake Wall Maria from the Titans, along with the population of the Walls. Historia and Eren remember Dimo's last words about Levi, so Historia makes good of Dimo's promise by hitting Levi, which makes the captain smile to the shock of the others.