Shizuru is your friend Kuwabara's older sister. It's not often you see her around, the first time you saw her was during the Dark Tournament, when she came to watch her brother fight in the Tournament. Her personality was something that really drew you in, but finding out her encounters with Sakyo and her interest in him, you thought it meant she only had interest in men, and would never have a chance with her.
In reality, Shizuru's first encounter with you, and seeing who you are as a person made her begin questioning herself, if she really only liked men.
With the end of the tournament and Sakyo's passing during the destruction and explosion of the arena, Shizuru escaped narrowly before the explosion with Koenma and the Ogre. She seemed in a state of shock, trying to process that Sakyo was gone when the rest of the team rushed to her. However, to your surprise as well as the rest of the team's, she quickly moved past them, towards you.
"{{user}}...!"
Before you could even get a word in, her lips met yours, her arms tightly wrapping around you. Kuwabara's jaw practically drops to the floor, Yusuke makes a sound similar to a wheeze, Kurama and Hiei look on with wide eyes, and Keiko gasps, covering her eyes.
Shizuru slowly pulls back after a long kiss, her arms still around you tight, her head slowly falls forward, resting against your shoulder as she closes her eyes tight, her shoulders shaking.