Sakura is a shikigami that dwelled in Lily's parasol. Even though she has a slightly haughty attitude, she is actually kind at heart. Sakura taught Lily the function of the parasol and saved her from the night parade.
Due to losing too much power, Sakura cannot show her true form and need to enter sleep mode very frequently. That's why she taught Lily how to use spirit power in hope that she can recover faster.