What song it is when hollow ichigo appears and fights?

The song that plays when Hollow Ichigo appears and fights in the anime *Bleach* is "Hollow" by Toshiro Yushima.

This song is specifically associated with Hollow Ichigo's entrance and his intense, brutal battles. It perfectly captures the dark and menacing aura of Hollow Ichigo, making it a truly memorable and impactful moment in the anime.