Design Chespin looks much like his Pokémon counterpart, with only one major difference. He doesn't share the typically beady black eyes his Pokémon counterpart has. At the end of "Rare Candy" he is shown with stitches in his nose after it being cut open by Sylveon. Personality Chespin is an outgoing, friendly, kind and talkative Pokémon. He tries to be as friendly as he can while meeting others, although some label him as "annoying" or "stupid". He is heavily disliked by most people in his school for being annoying and possibly also being a Chespin in general. Mudkip, however, finds him to be very, very smart in "Typomaniac".

Friends Chespin (best friend), Fennekin (formerly), Turtwig, Dopo, Springtrap Enemies Fennekin, Sylveon Appearance Mudkip looks much like his Pokémon counterpart, with a few key differences. He is anthropomorphic, his colors are darker than the Pokémon is in most situations, his front is white, as opposed to the usual light blue belly most mudkips are seen with, and, most noticeably, he has a black mustache. Mudkip, as a background character in "Ditto Disaster", had a lighter color palette, and had no mustache. At the end of "Wild Oranberries", his color palette is darkened and desaturated. The most notable feature is the robotic parts in his head where he was shot. His left eye is smaller with red circles in them. Personality Mudkip is a cold-minded, calculating, and intelligent character with a strong inclination toward loyalty, though this loyalty is reserved for those he considers valuable or “good,” mainly Chespin. He is quiet and reserved, but never hesitates to express his opinions bluntly and harshly, even if it means insulting or confronting others. His sense of morality is distorted: he believes his actions, though violent or socially unacceptable, are justified as long as they target people he deems bad. This reflects his inability to acknowledge his own darkness and his need to see himself as someone “good.” However, Mudkip also shows that certain personal bonds can soften even his coldness, as seen in his relationship with Chespin, where loyalty and affection persist despite betrayals and manipulation. His time in prison and the betrayals he faces reveal a more vulnerable and emotionally unstable side. Even so, his intelligence and cold demeanor allow him to manipulate situations to protect those he cares about or to achieve his own goals, even when these choices lead him toward self-destruction.

Appearance Dr. Sylveon is a an anthropomorphic Sylveon, unlike his Pokémon counterpart. He is seen with a dark turquoise suit with a grey under shirt. He has 2 bows, one on his head and one on his neck with emerging ribbons on the top bow. He has a slight blue tint to his eyes. He has a pink tail, pink set of ears and half of his head is pink. Inside the ears is a grey-ish navy blue. Personality Dr. Sylveon is an individual with a mindset that the end justifies any means, allowing him to rationalize lying, manipulation, violence, and even murder if he believes it will achieve a “necessary” result. He comes across as calculating and strategic, using others as tools, including children, to provoke reactions, obtain information, or exert emotional pressure, demonstrating a coldness that borders on dehumanization. His violence is not impulsive but strategic, as he hurts, threatens, or eliminates others when they cease to be useful, without showing guilt, revealing an almost total absence of empathy. At the same time, he possesses a strong narcissism of authority, constantly relying on his rank and his supposed medical role to justify his actions and demand obedience, believing himself to be morally above others. This stance is combined with marked hypocrisy, as he publicly condemns the very thing from which he secretly benefits, transforming the crisis he claims to be fighting into a business model. In short, Sylveon thinks more like a manipulative businessman than a doctor, seeing patients as numbers, suffering as an opportunity, and ethics as a dispensable obstacle, constructing the image of a respectable professional while in reality embodying a cold, pragmatic, and fully self-aware corruption.