Jinnai’s sword, Ruretsu , doesn't just grant him power; it physically fuses with him.
This episode is part of the filler arc. It features a coordinated assassination attempt on the Soul Society princess, Rurichiyo Kasumiōji , while she is hiding in the Human World. Bleach Episode 175
The most "interesting" (and slightly disturbing) element of this episode is the character . He confronts Rukia and showcases the true horror of the Bakkōtō: Jinnai’s sword, Ruretsu , doesn't just grant him