Sonia Acorn (Light Mobius) is the daughter of King Sonic and Queen Sally, and sister of Prince Manik Acorn. Sonia bears great resemblance to her mother, though has inherited her father's super speed and eye colour. She is princess of the Kingdom of Acorn and a member of the Future Freedom Fighters.
25 Years Later (Unaltered)
In the unaltered timeline, Sonia is the daughter and first-born child of King Sonic and Queen Sally, and elder sister of Manik Acorn. She was shown to be fond of Tails upon his departure for Downunda, unsurprising given his history with her parents. Along with the rest of her family she came to Angel Island to visit the family of her best friend, Lara-Su. She and a group of other girls soon enjoyed a sleepover, which Manik of course intruded upon. (StH: #137, #138, #139)
25 Years Later (Altered)
Due to Sonic's travel to the past, Sonia was erased from the timeline, putting a mental toll on the former king. However, after Shadow's defeat, Sonic brought up the idea of kids to Sally... (StH: #166, #167)
Five Years Later...
Five years afterward, Sonia was yelling at her brother Manik to move so she can see the TV and herself on it. She complained when she learned that her parents were going out for the night, but quickly changed her mind when she found out Lara-Su was babysitting them. She later caused havoc with her brother Manik, forcing Lara-Su to use Chaos Control to rein them in. Lara-Su then put them to bed and read them a few bed time stories, which seemed to put them to sleep. However, the two quickly sneaked out of their room and caused more trouble, resulting in a pillow fight with Lara-Su. The next day, they attended the celebration of the Five Years of Peace, when a missile was suddenly launched at the royal family. However, they were saved by the timely arrival of Silver the Hedgehog, who then explained to Sonic and Sally why he had come. Sonia then joined her mother, brother, and the unconscious Silver in fleeing to safety after the Dark Presence invaded the castle, though Sally had to carefully convince her strong-willed daughter not to go back and confront the intruders. She was later seen with her mother and brother in the Panic Room watching her father and a new group of Freedom Fighters re-take Castle Mobius. (SU: #5, #6, #7)
Water begins to flood into the Panic Room. Her father arrives before anything serious can happen. Doing as her father says, Sonia rode a rock as a surfboard, escaping the castle. The twins contribute to the efforts of the Future Freedom Fighters by reminding Sonic about his fight with Perfect Chaos and doing a spin dash with her brother after Sonic fails to hit the brain of Perfect Tikhaos. Sonia joins the team with her brother after the fight. (SU: #8)
The M:25YL Sonia is very mature and assertive, and has slightly more tolerance for her royal duties than her brother, who as first-born male, is heir to the throne of Mobius. Sonia was also best friends with Lara-Su, the daughter of Knuckles, once stating to her she "would hate to lose you as a friend."
The M:30YL version of Sonia is very fun loving due to being a child, and also gets annoyed with her brother easily. Despite this, the two both enjoy making trouble, especially with Lara-Su, whom both are affectionate of despite the near 20 year age gap between them. She is also strong-willed and dislikes the idea of anyone invading her home. Given her mother's efforts to avoid using the words "panic room" to describe their safe destination, it seems that Sonia is also highly excitable.
Sonia has inherited her father's super speed in the altered timeline. She also learned how to do the Spin Dash.
- Sonia is named after Underground Sonic's triplet sister, Sonia.
- In the Unaltered Timeline, Sonia had her mother's eye color, and showed no signs of superspeed. However, in the Altered timeline, she has her father's eye color, as well as superspeed.
- It was never explained why Sonia and Manik came out as separate children in M:25YL, but in Sonic Universe they came out as twins. Sonia had stated, as well as the Guardian Lara-Su, several times in M:25YL that she was older than Manik, but in Sonic Universe: #5, they are the same age. It may be possible that even though they may be twins, Sonia may still be older than Manik.
- In the Sonic In Your Face special, a character similar to Sonia appears in the future where NICOLE is created. She shares the same appearance and abilities as Sonia (namely super speed), but has blue eyes like her mother and her name is not mentioned.
Sonia is a brown squirrel/chipmunk with short auburn hair.
In the unaltered timeline, the teenage Sonia is largely identical to Sally in appearance. However, rather than her mother's typical blue, her outfit is purple, consisting of a leotard, vest, belt, boots and armbands. She wears a necklace with an acorn-shaped pendant. She is briefly seen in a pink single-piece bathing suit and, later, a pink and yellow nightgown featuring a smiley face on the front.
In the altered timeline, the much younger Sonia was given some slight variations in her basic appearance in response to the common fan complaint that child characters often look identical to their parents with no traits of the other. As such, this version of Sonia has her father's green eyes (though still mistakenly coloured blue on occasion), and her hair flipped up slightly in the front. She was most commonly seen in pajamas (green and pink, and then pink with white socks), and for formal public affairs, she wore a purple gown (depicted on a cover with a gold trim) with a small tiara. She often wore her hair in low pigtails.