Shizune is Tsunade’s right-hand aid and Dan Kato’s niece. She often gets dragged into Tsunade’s habitual gambling antics, and also takes care of Tsunade’s pet pig, Tonton. Ability-wise, she is a capable ninja, and was captain of the medical ninja team during the Fourth Shinobi War.
She also managed
to seal the three-tailed fox, but as for her character arc, she remains as Tsunade’s assistant, and never went beyond her duties or made any real impression on the readers or show watchers.
Though Shizune is well known for her great medical-nin, Sakura Haruno’s character outperforms her by a landslide, as she is able to unlock the Strength of a Hundred Seal Technique. Whereas Shizune, who has been under Tsunade's tutelage longer than Sakura, has yet to master the seal technique.
Overall, Shizune was a huge letdown, and many fans were underwhelmed by her character, since she appeared to have a lot of potential.