I believe she's referring to this particular Sakuya.
Thanks for the link, so short, yet so deep.
I love you, master.With all the love and respect from the bottom of my heart, I love you as my own parent.I couldn't be as competent as Youmu, nor as insane as Sakuya.Compare to anyone else, I am useless.But still, I...I can't live forever like the princess, Lady Mokou, or you, Master.But I am a useless apprentice.