Sonic the Hedgehog

Sonic the Hedgehog is the brother of Dragonizer the Dragon and a major character in Colleentale. His main motive is to capture a human so he can become a member of the Royal Guard, and finally have friends and popularity.

Normal ("Battle Body")
Sonic is a tall, perhaps anatomically inaccurate hedgehog with a head more mammal-like than his brother. Being spiky, many of his expressions incorporate a toothy grin. His eyes resemble a cyclops's; his spiky pseudo-brow form most of his expressions.

He wears his "battle body," an outfit that he created for a costume party. It includes a white chest plate with gold trim, orange-red gloves with gold trim, blue briefs with a golden belt, and knee-high, orange-red boots. A symbol that resembles that of Starman from the MOTHER series adorns the chest plate. He also wears a short orange-red cape.

Befriending (Cool Hog)
Halfway through the hangout with Sonic, he changes into his "secret style": a backward baseball cap, a t-shirt that reads "Cool Hog," small shorts with buttons, gloves with striped trim, knee-high socks, and sneakers. He also wears basketballs on his shoulders, likely Gumball Watterson's MTT-Brand FashionBall.

Penny Fitzgerald Hangout (Jog Boar)
During the "hangout" with Penny Fitzgerald, Sonic arrives wearing a sweatband, shorts, and a t-shirt that reads "JOG BOAR," with hearts on the pauldrons. He still wears his boots, gloves, and cape.

Personality
Sonic is a flamboyant hedgehog who presents a confident, charismatic image of himself. He works hard and, despite his brash personality, is kind at heart. He is optimistic and innocent even when the protagonist beheads him in a Genocide Route. He is also occasionally oblivious and nonobservant, but can be cunning at times, as seen when he uses reverse psychology to trick Amy Rose into befriending the protagonist.

Sonic believes in others just as much as he believes in himself. He has so much faith in his abilities that he waited outside of Amy's house all night and begged her to accept him into the Royal Guard. Seeing his persistence, Amy offered to train him but instead gave him cooking lessons.

He cooks chilli dogs in his spare time, though many characters seem to think that he is not very good at it. One of the reasons for this is because Sonic never ate chilli dogs himself to complete the chef's guidebook to cooking by tasting their creation before serving. He, therefore, cooks chilli dogs only because everyone else loves to eat it, indicating he does not play favorites. He loves puzzles and japes, as shown in the numerous puzzles he prepares for the protagonist as well as his collection of "complex tomes about puzzle creation." Though advanced puzzles may seem cerebral, Sonic also enjoys children's books and is somewhat childish with the decoration of his room. He also collects action figures.

Sonic also watches Gumball's TV shows, and admires Gumball so much that he would move to Hotland, a region that he hates.

Main Story
Sometime before the events of Colleentale, Sonic and his brother showed up one day in Snowdin and asserted themselves. Sometime after that, Sonic became friends with Amy and began training with her.

Neutral Route
Sonic first appears in Snowdin Forest, where he proclaims to Dragon that he will capture a human and become popular. Sonic, ignorant of the human hiding nearby, berates Dragon for not recalibrating his puzzles. Further in the forest, Sonic meets the protagonist for the first time, though he initially confuses her for a rock.

Sonic attempts to antagonize the protagonist with puzzles and japes, but he eventually warms up to her. He almost refuses to fight the protagonist out of pity. Though Sonic initiates an encounter, he never kills the protagonist and instead places her in his shed if her HP reduces to one. The protagonist can easily escape his shed.

Ultimately deciding that the protagonist is friendly, Sonic lets her continue into Waterfall, advises her on how to exit the Underground, and offers a hangout back at his house.

Returning to Sonic's home after Sonic's fight initiates the hangout. Sonic dresses in his "secret style" and hides a special gift under his hat for the protagonist. Ultimately, Sonic decides that the protagonist cares too much about him for her own good, and sends her back on her way with his phone number, which the protagonist can call at any time to hear his opinions about the room that she is in.

When the protagonist makes her way into Waterfall, Sonic attempts to sway Amy from killing them; Amy refuses to yield, however, and Sonic finds himself obligated to help her. He calls the protagonist and asks her to confirm what she is currently wearing. Sonic is loyal to both Amy and the protagonist by employing a ruse that backfires regardless of what the protagonist does.

If befriended, Sonic calls the protagonist while Amy is chasing her and say that they should all hang out. Backtracking to Amy's house during the chase leads to the protagonist discovering Sonic already waiting outside her house. After the protagonist chooses whether or not to give Amy water in Hotland, she can go to Amy's house, and Sonic offers speech based on the protagonist's actions after his call.

He flees from the hangout early on, after using reverse psychology to get Amy to befriend the protagonist.

True Pacifist Route
Befriending Sonic is necessary to finish a True Pacifist Route. Leslie guides him to call all the protagonist's friends to New Home.

Before Shadow the Hedgehog's boss battle, Sonic rushes to intervene with the battle between Asgore Dreemurr and the protagonist. He then meets Fluttershy for the first time and becomes annoyed once she tells him a pun.

Leslie then restrains Sonic and the rest of the monsters present with vines. Sonic defends the protagonist from Leslie's bullets and states his faith in the protagonist.

Epilogue
Sonic discovers that there is no need for the Royal Guard anymore and proclaims that this is "THE WORST POSSIBLE ENDING." He also comments that Fluttershy is a "HUGE HUMAN WITH AN ANNOYING PEGASUS COSTUME."

In the credits, it seems many of Sonic's dreams have come true: he drives a blue car along a highway, something he has always wanted to do. Later on, Asgore is shown trimming a hedge in the shape of Sonic's face, something that Sonic wished would happen once he became a famous royal guardsman.

Genocide Route
In a Genocide Route, Sonic pulls much of the same antics that he does in a Neutral/Pacifist route, except often cites the protagonist's unwillingness to complete his puzzles. He remains oblivious to the protagonist's motives until her battle, where he instantly spares her, wishing to guide the protagonist on a better path and be friends. The protagonist can then spare or kill Sonic.

The Protagonist
Despite wanting to capture the protagonist, Sonic still cares about her and eventually ends up hanging out with her if the protagonist does not kill him. Notably, Sonic hangs out with the protagonist even if she had been on a Genocide Route up until sparing him.

The protagonist remains friends with him throughout the movie and gains the ability to call him on the cell phone almost anywhere.

Dragonizer the Dragon
Dragon is Sonic's brother, and though Sonic often chastises him for being lazy and detests his many dragon puns dropped throughout the movie, the two of them care about each other a lot. Sonic often cleans up after Dragon and prompted him to get a job as a sentry.

Sonic is upset that Dragon naps so much and mentions that it's impressive how much slacking off his brother can do. Even though Dragon reads Sonic bedtime stories and is the sole provider in the hedgehog household, Sonic takes care of his brother and wonders what Dragon would do without such a "cool hog" watching over him. Together, they made Sonic's battle body as well as his cardboard sentry station in Snowdin Forest.

Sonic also recognizes that Dragon is secretive and kind of weird.

Amy Rose
Sonic and Amy are a good couple. After Sonic asked to join the Royal Guard, Amy gave him cooking lessons, and they bonded. Because Amy does not have the heart to tell Sonic that she will never let him join the Royal Guard, Sonic continues trying to impress her by capturing a human. Sometimes Amy grosses Sonic out, but Sonic looks up to her as a "lovely sow." Sonic is also oblivious at times when Amy is angry at him, though he is keen enough to know to present befriending the protagonist as a challenge to her.

Leslie
Sonic sees Leslie as a good friend because Leslie offers him predictions, flattery, advice, and encouragement. Sonic also borrows some of Leslie's speech characteristics, and Leslie guides Sonic to call the protagonist's friends to interrupt Asgore's battle with the protagonist.

Trivia

 * Like some other characters, Sonic has the same role.