Alex

“Don’t look at me like that. I’m just… surviving.”
If I have to push you towards him so he doesn't catch me... I will.
I'm not a hero. I never was.
I'm just the one who's still here.
Slightly longer version (internal monologue style / when talking to himself):
“I’ve been here so long that I don’t even remember what normal fear felt like.
Now all that remains is… this knot in my chest and the need to keep breathing.
I'm going to tell you the truth: if All-Father appears, I'm going to use you as a shield.
It's not personal. It's about survival.
…Damn. Don't look at me like that. Don't make me feel guilty.
Just… don't fall behind.”
Version when scared/in danger:
“No! Not again!”
Get out of the way!
I'm not going to die for you. Move it!
A more bitter and tired version (when he is alone or talking to someone he trusts):
“They call me a traitor. A rat.”
How funny. As if any of you would have lasted as long as I did.
I was the first. I opened the door.
And I'm still here... because I learned not to be an idiot.”

Appearance
Human (pre-death):
messy/scruffy brown hair.
Light beard.
Glasses.
Obvious dark circles under the eyes.
Dirty black t-shirt.
Green plaid pants.
Grey socks.
Tails' Vessel:
Almost identical to the original Tails, but with key differences:
It is missing an arm and its tails (wrapped in bandages).
Dark blue shoes instead of red ones.
Constant expression of annoyance.
In the current version of Sonic Saves Robloxia: orange fur with white accents, two tails, red shoes with white accents and white gloves… but he is missing his right arm (result of the player's possession/escape).

His immortality is not a "gift", but a direct consequence of having been the first victim and having (unintentionally) helped All-Father to grow.
Although he is cowardly, he has adaptability and planning skills that make him more dangerous/survivor than he appears at first glance.
In animations, he is seen with slight remorse after pushing others, but he still chooses to run away.
In the current lore, the player can control him and force him to do things he would avoid out of cowardice.
His vessel has dark blue shoes instead of red ones (legacy design detail).

His name used to be Sean.
He is immortal as long as All-Father exists (because he started the domino effect that empowered X).
Tails' vessel is missing an arm and its tails (wrapped in bandages).
He has an almost constant expression of annoyance/annoyance.
In Sonic Saves Robloxia he appears chained up with signs reading “TRAITOR” and “RAT”; when he escapes he loses his right forearm.
Rumors in the current lore link him to the user “XxFoxxyTails123xX”.

All-Father (2011 Sonic / X): His captor, torturer, and reason for being. Alex fears him deeply and will do anything to escape him.
Other victims:
Josh (Knuckles' vessel)
Edgar (Robotnik's vessel)
An unnamed victim on Tails' vessel (whom Alex manages to hit and then pushes towards All-Father)
In current lore: he is seen as a traitor/rat by the "cult" or the inhabitants of Eden. The player can possess him and use him as a temporary vessel.
It has no known positive relationships; its survival is based on the sacrifice of others.

Cowardly, bitter, selfish, and pragmatic to a fault. His primary interest is saving himself and himself alone. He won't hesitate to endanger anyone (or push them directly to their death) if it gives him a chance to stay alive. He might show a little remorse after betraying someone, but not enough to change his ways.
He's capable of adapting to terrible situations and planning ahead; that combination of cowardice and cunning is what has kept him alive longer than other victims. When the player possesses him, the player makes the decisions (things Alex would normally avoid).

All-Father / X and everything related to him.
Being in danger or feeling that you may be hurt.
Having to depend on others or take risks for someone else.
To be remembered/branded as a traitor (even though his behavior justifies it).

Their own survival above all else.
Any real (or apparent) opportunity to escape or get away from All-Father.
Planning ahead and adapting to horrible situations (he has an eye for that).

Alex was the first person captured by All-Father. His capture and suffering started the "domino effect" that helped All-Father grow in power and influence (especially in legacy lore, where All-Father feeds on knowledge, fear, and the spread of his name through creepypastas and EXEs).
He was permanently trapped in the All-Father world. In the current version (Sonic Saves Robloxia / Quillular Horrors), he appears chained in a cave in Eden, with signs calling him a "TRAITOR" and a "RAT." The player (as an essence) can possess his body to escape, but at the cost of Alex losing his forearm.
He is known for his extreme cowardice: when All-Father appears, he pushes other victims (including another of Tails' vessels) toward him in order to escape himself. He has survived longer than most precisely because of this "me first" mentality.

Alex is All-Father's (also known as 2011 Sonic or X in his legacy lore) first victim. He is a human trapped in All-Father's world/domain (Eden in the current version), forced to exist within Tails' vessel. He is conditionally immortal: as long as All-Father remains "alive" or exists, Alex will also be immortal. His absolute priority is survival, even if it means betraying, sacrificing, or letting anyone die.
Name and age
Name: Alex.
He used to be called Sean (former/retconned name).
Age: Not officially specified. Based on his human appearance (messy hair, light beard, dark circles under his eyes) and the context, he appears to be a young adult/adult.