I really liked the description of this setting in the interest check and the characters posted so far.
Character below, it's mostly done though I might change it a little, let me know what you think and feel free to make constructive criticism!
Thanks.
Appearance:
Name: Argo Mihhailov
Age: 21
Gender: Male
Nationality: Estonian
Personality: On the surface, Argo is curious, hard-working and friendly - he likes talking to people and getting on with them. He enjoys playfully teasing others to get a reaction and loves an in-joke or two. He is sympathetic, but doesn't care for people who complain too much about too little. Holds strong beliefs about certain topics and is resistant to change them.
Background & Death: Argo and his family moved to England when he was a young child. His father was well-educated and was able to get a successful job. Argo was instilled with the virtues of hard-work and dedication and did well in school, college and ultimately university. Active and sociable, Argo was never short of company. During his final year of university however, Argo fell seriously ill and was admitted to hospital a number of times. Numerous tests were performed but results were almost always inconsequential. Argo's condition worsened and he was admitted to hospital for the last time shortly after his 21st birthday. Surrounded by his loved ones and exasperated doctor's, he slipped into a coma and passed away.
When 'revived', Argo was fiercely determined to remain near his family, watching over his parents and siblings, sharing in their moments of joy along with their moments of sadness. Ultimately it proved too painful to stay, and Argo finally listened to the urging feeling within him (and his Mori) that he must complete his mission and realise whatever it was that he was brought back for.
Appearance:
(To be honest I feel like this Mori shouldn't really have a fixed physical form due to it's nature, explained below. Maybe its form can simply vary depending on what is going on. I picked the Cheshire Cat imagery partly because I really appreciate it, but also because I believe it conveys what I'm trying to say.)
Name: Argo knows him only as "Shifty".
Represents: Death seemingly caused by the unknown.
Abilities: You know me not -The cause of Argo's death took no recognisable form for those who witnessed it. Stemming from this, Argo can alter anything about himself (his face, body, voice) to deceive others. He is a very convincing liar. With more time and concentration and with the aid of a photo or similar, Argo can become a replica of another; if he observes them at length he can also adopt their mannerisms to enhance the realism of the impersonation. (I'm thinking this ability has the potential to grow more advanced, affording Argo the ability to quickly shift form completely into other animals or beings, inanimate objects, or camouflage himself.)
Emotional volatility - At the time of Argo's death both he and his family had gone through emotional turmoil. Sadness and anger were primarily there, along with frustration. Towards the end Argo realised he had to remain strong and level-headed for his family's sake. Shifty provides Argo this cool, calm and collected demeanour in the afterlife, allowing for performance under pressure. Argo is vaguely aware of the emotions of people close by - whether they're happy, sad or scared for example. Though he hasn't completely figured out how to use this to his advantage, partly because if he 'absorbs' too much emotional info he becomes very unstable with wild, out of character mood swings. (Not entirely content with this ability, might tweak it, ideas welcome).