Ace Byeler

Loss X:
Their fundamental relationship. Ace is one of his Vessels and a victim. The relationship doesn't appear to be friendly, and Loss uses the connection with the Vessels as part of his existence in the world.
Amelia:
She is also a Vessel from Loss X and therefore shares the same universe and situation as Ace. Available information describes Amelia as someone who is afraid of Ace due to his unpredictable behavior.
Other Vessels:
Ace has a particularly bad reputation among them because of his cruel behavior.
His father:
It is probably the most important relationship from his human past. The lore establishes a very complicated family history and a deep resentment towards him.
His mother:
She's much more mysterious. We know Ace took her surname and that he appreciated her cooking, but the wiki still doesn't reveal much about her.

Little-known things
Some details that are easily missed:
Ace is not his original name. His birth name is Vladimir.
He took his mother's surname.
His father was Russian.
The nationality/origin of her mother is not yet specified.
The events of his story take place in Canada.
His character was created in November 2025.
His favorite food combines pizza and Orange Fanta, while he also has a fondness for his mother's cooking.
His favorite Sonic character is Scourge, not Tails.
It is listed as one of the oldest Vessels in Loss X.
His design of Tails deliberately retains many elements of Tails, but the eyes, shoes, quills, and expression serve to distinguish him.

Here's the interesting part.
Loss X is the entity responsible for his situation as a victim/Vessel, and Ace is one of his main Vessels. Available information states that Loss can use the bodies of Sonic's Vessels to manifest.
Ace, therefore, has a particular reason for confronting other Vessels related to Sonic: he is trying to prevent Loss from manifesting through them.
This makes their violent behavior towards other Vessels something more specific than simple cruelty.

Specifically mentioned are:
He hates Sonic.
He hates his father.
He has an extremely negative relationship with people connected to his past.
Its behavior towards other Vessels is cruel.
And there is a very important connection between his hatred for Sonic and his existence as Vessel

The explicit data I found:
🍕 Pizza
🥤 Orange Fanta
🍳 The food prepared by his mother.
🦔 Scourge the Hedgehog is his favorite Sonic character.

Sarcastic
Smug
Mocking
Cruel to other Vessels
Provocative
Quite ruthless
One of the oldest and cruelest Vessels in its group.
But there is an interesting contradiction that can make the character much more complex: his current behavior does not necessarily represent how he was originally as a person.
Her family history shows that she had an extremely troubled childhood and a terrible relationship with her father. The lore establishes that she suffered domestic violence and developed a deep resentment towards him.

Human appearance:
There's a significant gap in the public information here. Ace's profile doesn't provide a detailed physical description, so it's not advisable to invent details like hair, clothing, exact age, height, etc.
What we do know is that his birth name was Vladimir, chosen by his father, and that he later adopted his mother's surname. It is also specified that his father was Russian and that his mother's identity has not yet been revealed.
Appearance as Tails
This part is quite well defined:
Ace looks almost exactly like Tails, but he has his own differences:
Yellow fur.
Jade green eyes.
Eyes different from those of the conventional Tails.
Its spines are slightly longer.
Her shoes are jade green instead of red.
His expression is much more boastful and mocking.
His appearance conveys confidence and provocation rather than the more vulnerable expression associated with Tails.

That detail about the shoes is interesting because it makes Ace recognizable even without changing Tails' design too much.

Name: Ace Byeler.
Real name: Vladimir.
Gender: male.
Pronouns: he/him.
Species: originally human, later Tails' Vessel.
Vessel: Miles "Tails" Prower.
Creator: Giga Mobi.
Character debut: November 27, 2025.
Universe: Loss X.
Location of the events: Canada.