Trevor Troublemeyer is the main deuteragonist of the series. He is Eric Needles' best friend and partner-in-shenanigans and can always rope him into all sorts of hijinks.
Trevor wears a Prussian war helmet. He has black hair that sometimes attaches to his helmet, while in more than one occasion he is seen without his helmet and he still has hair; so it's unknown if he's actually bald. His shirt has the Roman numeral for 2. He also wears purple jeans, copper earrings, and a light green traveler's jacket. Even if he has the same age as his friends, he has some features that signify that he is slightly older, since he has hair on his legs and under his armpits, unlike everyone else.
Trevor isn't the most bright out of all of his friends, although he has had some bright moments. Trevor, (having a bloodline of evil) likes destruction and mayhem, like his father's alter-ego, and usually goes on an evil rampage either sometimes or when needed to.
Due to having no brain (as revealed in Gone Gaga), Trevor has the lowest intelligence, as he wanted to touch numerous gadgets within the Mansion (including poop). In Ice to Know You, he believed that the weather-changing machine can cook hot dogs, though Eric debunked this.
Eric is Trevor's best friend, and they do almost everything together. Trevor is usually the one who gets them into trouble, leaving Eric to think of a way to get them out of it. They sometimes fight, but in the end, they are friends again.
It is said that Trevor dislikes Kitty on the YTV Sidekick page, but it hasn't been shown that much in the series. The only known conflict was shown in 'The Henchman Challenge' when Kitty didn't like Trevor making Eric cheat. Along with that, Trevor wasn't fond of Kitty making Eric play fair. Other then that conflict, they don't fight often. Though in some episodes, Kitty shows annoyance to Trevor's stupidity.
Vana gets along well with Trevor, but not as much as Eric. He doesn't do as many things with her as he does with Eric, but they seem to get along sometimes. Unlike Trevor, Vana is more mature and focused than him.
- Trevor is the only sidekick to live in the evil side of town.
- His middle name is Trouble.
- It is unknown why XOX sent Trevor to the Sidekick Academy. Possibly, it would've been to destroy it.
- Trevor is voiced by Christian Potenza, the voice actor of Jude from 6teen and Chris McLean from the Total Drama series.
- For some reason, in "Stupor-ize Me", he fears (and despises) the word "work".
- He doesn't know that his dad, Mr. Troublemeyer, is the supervillain Master XOX.
- In 'Four's a Crowd', Trevor claimed he had never noticed a laboratory in his house before, yet in 'Maxum Mom', he asked his dad if he could borrow the lawnmower to get some snacks while he was in the lab.
- Due to his evil bloodline, he always has a plan to destroy the school.
- Trevor had dressed up like XOX four times in the series.
- In "Like Supervillain, Like Son" he dressed in a suit like XOX when he teamed up with him.
- In 'Halloweenie' he dressed as half XOX and half Maxum Man for his costume.
- In "Four's a Crowd" he 'borrowed' one of XOX's suits and his powers to be a supervillain.
- In "The Spark is Gone", Trevor wins the award of "Seventh Best Doofus".
- It has been hinted many times in the series that he is evil, but he has shown to also be good. It is possible that he might be both, depending on the situation.
- Trevor seems to be both a fan of Maxum Man and Master XOX, but it was never shown who he likes more.
- Trevor is now a member of the Cranials, a group of supervillains in the episode "Insane in the Cranial".
- Trevor has had a habit of continuously accidentally hampering Eric in his approach operations to Vana. When Eric managed to snatch an invitation from Vana for a movie, Trevor unwittingly pushed him, ending up with Vana hitting the garbage can and sending her into a rage; when Eric was about to kiss her for a script, Trevor sent down the hatch on top of which the girl was, making her fall below.
- His last name is a pun on troublemaker. This is a reference to him being a son of a supervillain.
- According to some fans, Trevor is 14. However, according to Todd Kauffman, he is 13.