Sinedd, like the rest of the Snow Kids was born on Akillian right after the explosion. Durring the Flux War his parents were killed leaving him as an orphan. It is unknown who took care of him after that but most likely he grew up in an orphanage. Sinedd doesn't appear to have the Meta-Flux inside of him like the others. It is presumed that it didn't manifest in him because he never got to use the Breath of Akillian, which is srtongly connected to the Meta-Flux. However, he has completely harnessed the full power of The Smog (flux of the Shadows) and equals D'Jok. Unfortunately due to intense use of the Smog Sinedd is starting to suffer psychological and physical consequences- he is getting more and more violent on the field and deals with sudden attacks of pain.He has a certain inhibition towards Rocket as he never challenges him. Rather, he asks Rocket to join the Shadows, an indication of the fact that Rocket has great ability which Sinedd respects.
He's an exceptional Striker with a lot of kicking power. Unfortunately, Sinedd rarely passes to the other players causing him to be shunned by the rest of them. After an argument with Aarch and the return of Tia during the Red Tigers' match, Sinedd met Artegor Nexus, who used Sinedd's anger and offered the boy to come with him. Sinedd quickly agreed to join the Shadows.
Sinedd is pessimistic, arrogant and proud. Rather direct and violent when it comes to football, which can be the effect of growing up without any family or friends, Sinedd is the type who gets to work quickly and his aggression on the field has led to him being frequently penalized for fouling other players. Brought up in Akillian's poorer districts, he has apparently known D'Jok, Micro-Ice, Ahito and Thrann as long as they have known each other and has a long-standing antagonistic relationship with D'Jok and Micro-Ice.
Disliked for his arrogance, Sinedd doesn't get along well with any of the other team members, though he does show a grudging respect for Rocket, whom he may have shared a room with during the short time they were both on the team and whom he invited to join the Shadows. Old rivalries with D'Jok led to friction on the pitch and the two were never able to develop a solid partnership, a problem which sabotaged the team's attack position. After leaving the team Sinedd and D'Jok's long-standing rivalry escalated, until beating D'Jok and proving his worth became the most important thing on Sinedd's agenda.
Sinedd plays at Number 11, Artegor Nexus's old number. His defection from Akillian to the Shadows echoes Aarch and Artegor's move of fifteen years previously.