We don't know much about Xavier yet as he is a new character in Falcon Claw University. All we know is that he is working for Derek. At the end of "Trying To Protect You", we see Xavier running at Aaron, tackling him. The episode then ends with Jenny shouting "Aaron!" in fear. In the next episode, which is "Aaron's Rival", Aaron attempts to fight back and Jenny threatens Xavier to hit him with a stick if he doesn't stop. It is then revealed that his name is Xavier when he tells Aaron about how they are childhood friends. It is revealed later on in the episode that the fact Xavier and Aaron are childhood friends turns out to be fake and that Xavier made it up. Xavier is actually a new high-class agent hired by Derek to prevent Aaron from killing anybody. Agent R suspects he is some kind of undercover field agent, specialized with blending in, allowing for Derek to supervise Aaron on new grounds such as at the café and in class.
Even as a new recruit, Xavier was given higher authority than the other agents. Derek informed Xavier just about everything about Aaron including Aphmau, the person Aaron was forbidden to be in contact with and even the secret of Aaron being an Ultima. Xavier took full advantage of this knowledge. When he and Aaron met, he asked how Aphmau was to make his made-up story more believable. Xavier also took it upon himself to mockingly convince Aaron to use his bandana again numerous times. It wasn't until it was convenient for him that Xavier told Aaron that he knew about him being an Ultima. He then cryptically informs Aaron that his friends will be his.
It didn’t take long for Xavier to start interfering with Aaron’s social life, telling lies to Aaron’s friends to gain their trust. He also took time to bully Aaron. He was later seen spying on Aaron, being surprised to see that Aaron has a phone. He saw Agent R take it from him and decided to confront the agent. When Agent R said he was going to report this to Derek, Xavier objected, saying he wouldn’t get to pick on Aaron if he got in too much trouble. Claiming to have higher authority, he demanded to hand over the phone. Xavier then noticed that Aaron left a text for him and Jenny to meet at the mall. Despite being thrown off track, he was able to track Aaron on campus and saw him with Jenny. Xavier sent Aaron to his room and left without answering any questions Aaron had.
He butted into another conversation Aaron was having with his friends and heard they were going to the beach. Xavier decided to come along with Diana to make Aaron feel more uncomfortable. While at the beach, his motives were slowly starting to unfold as he started flirting with Jenny, who he believed Aaron was close to. When back on campus, Xavier noticed Aaron having a relationship with Aphmau, claiming it to be interesting.
He butted into yet another conversation when Aaron was trying to tell Jenny how he only saw her as a friend. Later, he is seen chatting with Jenny in class, hoping to get Aaron jealous. Under mumbles, Xavier’s true malicious plot has been revealed. All this time, he had intentionally plotted to make Aaron angry. His plan was to expose Aaron’s true nature to the world, the exact opposite of what he was hired to do.
He is later seen on social media trying to explain to his friends that he is a secret agent and that Ultimas are real. When they don't believe a word he says, he tosses his computer into a wall. He also takes note that flirting with Jenny isn't triggering Aaron as much as he thought. He decided to spy on him more, noticing him trying to avoid Jenny and not having new friends. He then saw him talking with Aphmau and decided to search his room, pushing Agent R out of the way and telling him he is not very good at his job. Xavier managed to find a picture of Aaron and Aphmau under the bed, claiming that he found the jackpot. The next day, he put his plan into action by practicing soccer with Aphmau, having also told Aaron not to go out. Aaron eventually saw Xavier with Aphmau, to which Xavier took advantage of Aaron's emotions. After faking an injury and having Aphmau walk him to his room, he asked her if they could go for coffee later.
Once he spots Aaron again, he attempts to kiss Aphmau as he takes out a camera to record Aaron's eyes. The plan backfires when Aphmau kicks him in the coconuts, causing him to pass out. He awakes several hours later and rushes to his dorm, only to find it being searched by several of Derek's men. Derek himself comes up to Xavier and reminds him that he hired him to protect his son, only to find that he was planning to expose him for something he's not. Xavier is then taken by force to an unknown location.
In general, Xavier has shaggy brown and dirty blond hair with orange eyes. He wears a white sleeveless T-shirt with blackish blue jeans and gray bracelets.
Not much is known about Xavier, considering his freshness in the series, but he seems pretty extroverted. He also seems to be slightly cynical in outlook on life, but also appears to be a realist. He lies easily to win people over and has a slight silver tongue. He is slightly mischievous in nature and acts like quite the ladies man. He is also an expert at seemingly popping out of nowhere. He also knows when people trick him, but he plays along so he could make a comeback when they least expect it.
He clearly takes joy in getting Aaron frustrated, such as sarcastically saying he is not spying on him, lying to or in front of Aaron's friends, pretending to be his childhood friend even after admitting he lied, being cryptic, ignoring questions Aaron has about him and tossing away objects that takes Aaron’s interest. When Aaron said that he never had any problems with his eyes in public, Xavier decided to tell Aaron to thank Derek for making sure that’s not the case when in fact he unintentionally does the complete opposite.
Even though he was hired by Derek, Xavier seems to work on his own motives. One example being committing physical assault on Aaron before introducing himself, something no other agent hired by Derek has ever done. He’d also rather not have Derek know stuff like Aaron having a phone, so he could torture Aaron more. Xavier was also told to make sure that Aaron stays away from a girl with black hair. When he ended up catching Aaron in the act, instead of reporting to Derek right away, he decided to play along just to get on Aaron’s nerves. He is also seemingly plotting something malicious, possibly even behind Derek’s back. This was confirmed that he had intentions of exposing Aaron as an Ultima by triggering his eyes. If he were to expose Aaron, he wouldn't care less on how society would mistreat him.
- Xavier is also the name of a guard in the Minecraft Diaries era who created the Jury of Nine. It is suspected that the Jury of Nine was started to protect Irene, whom Xavier loved and guarded.
- Xavier is the basque name meaning "bright". Xavier is also the name of Saint Francis Xavier.
- There are several hints that suggest that Xavier is actually a werewolf.
- Derek shows no concern over Xavier’s safety despite his beliefs of Aaron being unpredictable. Xavier himself is not afraid of Aaron’s eyes as he is trying to trigger them, but shows some concern for his life.
- He possesses great strength as he was able to pin Aaron to the floor on their first encounter.
- He is able to easily track down Aaron’s location even when he is led on a wild goose chase.
- On the beach, he was revealed to be very athletic.