Timeline/Headcanon
-26 years from canon: Born
-25 to -18 years from canon (ages 1 to 8): Grows up for indeterminate amount of time before her parents are killed (assuming she lived with them and wasn't abandoned), she receives her first Mashou, she acquires her demon blade (closely linked to/based on the Kusanagi-no-Tsurugi), and ends up living with snake demons for another indeterminate amount of time- not necessarily in that exact order
>Because she (appears) to remember her time with the demons, I'm going to TENTATIVELY say she made a contract with them for survival, instead of saying she was possessed by them.
>This likely didn't happen any earlier than 5 years of age
-17 years from canon (age 9) Shiro finds her, whoops the humanity back into her/seals the demons into her blade, takes her back to True Cross Academy
>Her and Mephisto got along horribly. She was destructive, filthy and liked breaking his figurines.
>Put into foster care but allowed to continue learning to be an Exorcist at True Cross Academy under Shiro's instruction. Mephisto pays for her enrollment.
>Not a happy child! Bounced between foster homes frequently
-15 years from canon (age 11): Rin and Yukio born; Shiro becomes increasingly scarce
>Loooooots of conflict between them at this time; this is when Shura considers herself having been "cast aside"
-11 years from canon (age 15): Enrolls at True Cross Academy as a full-time student, meets Arthur
>They proceed to immediately beat the shit out of each other and are rivals/hate one another from then on
>She takes to her studies surprisingly well, even if she appears to slack off
>I am going to TENTATIVELY say this is when she got her tattoo, until canon says otherwise.
-8 years from canon (age 18): Leaves foster care to live on-campus full time
-5 years from canon (age 21): Meets trollbait Yukio, harasses him like nobody's business
>Takes and passes qualifying Exorcist exams for multiple Meisters (Knight, Aria, Tamer, Doctor)
-3 years from canon (age 23): Leaves for the Vatican to become an Inspector shortly after
-1 years from canon (age 25): asked by Shiro to take care of Rin should he die. Cuts all ties with him as a result
-0 years from canon (age 26): Assigned to kill Rin, nearly does but decides to take him under her wing instead, LALALA THIS IS ALL CANON.
-25 to -18 years from canon (ages 1 to 8): Grows up for indeterminate amount of time before her parents are killed (assuming she lived with them and wasn't abandoned), she receives her first Mashou, she acquires her demon blade (closely linked to/based on the Kusanagi-no-Tsurugi), and ends up living with snake demons for another indeterminate amount of time- not necessarily in that exact order
>Because she (appears) to remember her time with the demons, I'm going to TENTATIVELY say she made a contract with them for survival, instead of saying she was possessed by them.
>This likely didn't happen any earlier than 5 years of age
-17 years from canon (age 9) Shiro finds her, whoops the humanity back into her/seals the demons into her blade, takes her back to True Cross Academy
>Her and Mephisto got along horribly. She was destructive, filthy and liked breaking his figurines.
>Put into foster care but allowed to continue learning to be an Exorcist at True Cross Academy under Shiro's instruction. Mephisto pays for her enrollment.
>Not a happy child! Bounced between foster homes frequently
-15 years from canon (age 11): Rin and Yukio born; Shiro becomes increasingly scarce
>Loooooots of conflict between them at this time; this is when Shura considers herself having been "cast aside"
-11 years from canon (age 15): Enrolls at True Cross Academy as a full-time student, meets Arthur
>They proceed to immediately beat the shit out of each other and are rivals/hate one another from then on
>She takes to her studies surprisingly well, even if she appears to slack off
>I am going to TENTATIVELY say this is when she got her tattoo, until canon says otherwise.
-8 years from canon (age 18): Leaves foster care to live on-campus full time
-5 years from canon (age 21): Meets trollbait Yukio, harasses him like nobody's business
>Takes and passes qualifying Exorcist exams for multiple Meisters (Knight, Aria, Tamer, Doctor)
-3 years from canon (age 23): Leaves for the Vatican to become an Inspector shortly after
-1 years from canon (age 25): asked by Shiro to take care of Rin should he die. Cuts all ties with him as a result
-0 years from canon (age 26): Assigned to kill Rin, nearly does but decides to take him under her wing instead, LALALA THIS IS ALL CANON.