Character Description: Shiori
Shiori is a very young hanyou. Her mother was a human and her father was a bat demon. Shiori came from a family line (her father's) that could create a powerful barrier around the entrance to the lair of the bat demons. Shiori's grandfather, Taigokumaru, wants Shiori so she can maintain the barrier.
InuYasha and company came looking to kill a demon that could set up strong barriers and kill them, not realizing that it was the little Shiori that sets them up.
In the end, InuYasha killed Taigokumaru with Shiori's help and Shiori allowed InuYasha to cut a red ball (called a blood crystal) that let her create the barriers.