It took Soi Fong twenty years after Yoruichi-sama's departure to stop looking over her shoulder for her mistress. Normal bodyguards would have been able to look in front at the person they were following, but Yoruichi-sama was always irritating that way. (And wasn't that part of her charm?) She was where she wanted to be, and it was Soi Fong's job to find her and catch up.
Far too often, she was behind Soi Fong, and smiling. She would lean over Soi Fong's shoulder, and prop her folded arms on Soi Fong in the most casual and trusting way, and whisper something in Soi Fong's ear.
After fifty years, Soi Fong began to grow used to Yoruichi-sama's absence. Nobody else leaned on her like that. (Nobody would dare.) Even the older captains, whether they were avuncular or cheerfully lecherous or simply strange, didn't . . . touch her. She didn't touch people. (Suzumebachi didn't count.)
She liked to think, occasionally, that she was doing a good job.
When the queen is gone, Suzumebachi would hum in her sleep, then there must be a new queen.
There were areas of thought which Soi Fong didn't touch. They covered topics such as Walking Out On One's Responsibilities, Walking Out On One's Division, and Walking Out On One's Covert Operations Group. She didn't think about them at all.
And she never, never thought about Walking Out On The People Who Love You, because some concepts were simply too painful even to formulate.
She got on with things and took command and became stronger, and for every time she might have thought, Yoruichi-sama would have approved, she would counter it with she deserted and let it lie there, before the words left me or betrayed me could so much as enter her mind.
Ultimately, she knew that she could walk out on the Division herself, and go to find Yoruichi-sama (for surely Yoruichi-sama could not hide forever), and fill that part of her duty which said she was Yoruichi-sama's bodyguard and servant for life. Or maybe kill Yoruichi-sama for leaving her. She wasn't quite sure.
But some part of her didn't want to leave her duty.
It would have disappointed Yoruichi-sama.
And she didn't want to do that.
Soi Fong never did manage to stop giving a scornful, disdainful, frustrated little sniff when someone nearby did something stupid.
Even when it was Yoruichi-sama.
(And even, sometimes, when it was Soi Fong herself.)