|Friends||Blastus, Weenus, Emily Omika, Frankie Lizzar, Alice Benar, Megawatt, Tacklebot, Maimy, Thunderbite|
|Enemies||Megawatt (formerly), Dreadnot|
|Love Interest||Maimy (formerly), Emily Omika (currently)|
Thrasher is the main protagonist of Robotomy. He is a tall, tan, and skinny robot who seems to be pretty apathetic, and full of the angst of an average teenager. He is very uptight and tries to avoid conflict, but always gets suck in Blastus's poorly thought out schemes. He is voiced by Patton Oswalt.
Thrasher is tall, tan, and skinny. He has spikes on his broad shoulders and skinny head.
A tall, lankly robot who isn't very confrontational. Though calm and reserved, he often falls prey to Blastus' badly-thought out schemes. Despite that, he's always at his side. As aforementioned, he is quite uptight, and apathetic. Usually when it comes to male robots, like Blastus, he simply shows no care for their problems, unlike with fembots. So far, the only known fembot that he's shown apatheticness towards is his baby sister, Mecha Jodi, despite her psychopathic murderous tendencies. He also tries his best to avoid conflict, and can easily be scared when conflict is about to start, as shown in From Wretchneya with Love, when he starts shaking as Blastus's fiancée yells at him. Even so, at times he is shown to be able to confront people, as well. When around love interests, such as Maimy, he tends to do whatever it takes to be with them, even going as far as to donate his own coolant many times, despite knowing the various consequences.
- Blastus - Thrasher and Blastus are best friends and have been for most of their lives. Thrasher isn't always willing to go along with Blastus and his crazy ideas on things they could do and he is always hesitant to do it. However, he is always getting reeled into it. In Big brother Thrasher, Blastus is revealed to be Thrasher's little brother. In the episode Sumo Thrasher, Blastus admits that he loves Thrasher no matter what and that he is more imoprtant to him and the girls more than anything else.
- Maimy - Maimy is Thrasher's love interest. Despite the fact that Thrasher tries his best to become her boyfriend, his attempts always seem to fail. In the episode Bling Thing, it was shown that Maimy and Thrasher were about to become an official couple, and smash each other with hammers, until Maimy got crushed by Gorgon, and seemed to have gotten mad at him, causing Thrasher to give her a raincheck. In the episode El Presidente, after Thrasher became school president, Maimy started growing an interest in him, beginning their boyfriend-girlfriend relationship. Maimy also said that she has had a thing for Thrasher since Kindergarten, and only dated Megawatt to make him jealous. Of course, it is unknown whether this is true, or not. They stopped dating after she overthrew him as president, for a short amount of time. It is unknown whether, or not they are ever going to become an official long-term couple. However, Thrasher lost feelings for Maimy later on and now has feelings for Emily.
- Nana - Nana was first introduced in Nana's Run, after it was revealed that she had a few hours left until she had to explode. She is Thrasher's grandmother, and it is shown that Thrasher really loves her, and was crushed when she was about to die. Thrasher and Blastus took her out for a few hours, so she could complete her bucket list, before being sent off to another planet. After a few hours, she became insane, and started eating other robots. After she attempted to eat Blastus, Thrasher had to blast her off, even though it seemed to hurt him having to do that.
- Mecha Jodi - Mecha Jodi is Thrasher's baby sister. She doesn't seem to like him, and it is possible that he feels the same way about her. He constantly has to put her in a cage, due to the fact that she is known to destroy things in a psychotic rage.
- Frenemy - Frenemy was briefly a friend of both Thrasher and Blastus. They both attempted to get rid of him, after he started annoying them with his clinginess, and blocking all of their friend requests out of jealousy.
- Thunderbite - Thunderbite is Thrasher and Blastus's principal. They seem to get along with each other, as Thunderbite loves all of his students. He even gave both Thrasher and Blastus advice of how to get rid of Frenemy for a while, by switching to another site called Squeeker.
- Megawatt - Thrasher is jealous of Megawatt, as he is going out with his love interest, Maimy. Megawatt doesn't seem to acknowlegde his existence so much, however, and when he does, dimisses him as a nerd. They are basically love rivals.
- Emily Omika - Thrasher and Emily are friends. They are shown to have have fun in sports, even she gets ultra hyper and super fast. However, his friendship with her blossoms into a crush when Thrasher realized Emily has feelings for him since kindergarten.
- Frankie Lizzar - Thrasher met Frankie along with Blastus when they were little kids.
- Alice Benar - Alice and Thrasher are friends.