A literal contrarian by nature, the Amanojaku known as Seija Kijin has earned herself quite the reputation. A weak youkai with the power to flip things around, her sheer existence makes her stand in opposition to the world around her. She dislikes what others love, and thinks differently from her peers. Making others happy is something which she abhorred.
Due to her weak status and inability to move higher on the food chain of power, she was dissatisfied with her lowly status in life. She’d do whatever is in her power to get what she wanted, and had no qualms using and deceiving others to get it. Allies and acquaintances were only useful so long as they got her to where she wanted to be.
Friends are unnecessary - she’s perfectly happy being hated. After all, she’s an Amanojaku - why would she enjoy being liked? The only use she has for a friend is as a stepping stone, to boost her closer to achieving her goals - and she’s made that sentiment perfectly clear.
After all, that’s the only reason why she approached the Princess of the Inchlings, isn’t it? The only reason she fed her lies and fabrications about being oppressed, and gave her the means to turn the realm’s political hierarchy on it’s head? The only reason she fed her nonsense about being brothers in arms, friends with a common goal.
Sukuna Shinmyoumaru was just a tool to get her closer to being on top, and the naive princess ate up everything she said, agreeing to her plans and then some. That naive princess was thrown away as just like a broken tool soon as her usefulness had ended, leaving the poor girl to take the fall for the entire plan she orchestrated, at the mercy of the shrine maiden who came to resolve the incident.
But her deception wouldn’t remain hidden. As soon as the lies she had fed the princess had come to light, Seija found herself in a plight of her own. Actions hadn’t been without consequences - someone had put out a bounty on her head. She’d been outed as the one who had tried to overthrow the balance, and the realm was out for blood.
Now a fugitive on the run across the realm, she’d hide and steal to evade capture, using the items she’d stolen along the way to cheat her way through the ever-increasing attempts to catch her. Gensokyo’s big-shots were after her head ... but, if she wanted her plans to succeed, then she just needed to beat them, yeah?
She won the battle, but lost the war.
The incident she’d caused had been squashed, and all the allies she had made lost in the process. But that’s fine, isn’t it? She’s an Amanojaku - it’s not like she liked having friends anyways.