This filler arc is pretty damned good. It isn't dragging, the fights are brilliant, and the characters seem to be revisiting their original motivations for fighting. There's also some wonderful insights into other characters, like the one who has recently taken over my brain, Hisagi Shuuhei.

Where's he going to attack from?

Behind!

You missed!

I'm not that weak!

Cheat!

*gets distracted by plotbunnies again*
There's more fights than just the Hisagi/Kazeshini one though. Ichigo vs Zangetsu take two is also going on elsewhere.

Where'd you come from?

Look, mum, I can wield my sword one-handed!

Hichigo's too cool for gravity.

I think Ichigo's starting to learn how Byakuya felt that one time.
Renji is also fighting the Zabimaru pair: a fur-covered baboon woman and a cute little snake boy. I love those two, and I think I actually prefer them to the Zabimaru shown during the manga-based Soul Society arc.

Did you have to pull me into your boobs, Monkey?

I know they're not, but Renji looks like he's got freckles right now.

Most people would kill to get so close to Monkey's boobs. Snakey just looks annoyed though.
Hisagi isn't doing so well in his fight. The reason why he hates Kazeshini, a being who is normally a part of his own soul, is the very same reason why he's losing now. Kazeshini's dual blades are fast and deadly, and it looks like it might be the end for Shuuhei...

...until Izuru comes to the rescue.

Shuuhei isn't content to stand back and let his kouhai fight for him...

...but Izuru is determined to defend his sempai.

This really doesn't look like a fair fight.

Shuuhei realises that listening to the former healer when he tells you not to move is probably a good idea...

..but he still tries to stay conscious to watch the fight...

...for all of a couple of seconds.

Kazeshini isn't impressed by his new opponent...

...and tries to intimidate him...

...by running his tongue along a razor sharp blade.

I wonder if Shuuhei would have fallen unconscious so quickly had it been anyone other than his trusted kouhai there.

Izuru learns quickly that Kazeshini's dual scythes can come from any direction...

...and that Kazeshini himself is just as tricky.

Izuru, though, is not so easily tricked, and Kazeshini discovers why you should beware of kidou masters.

Izuru takes Shuuhei to safety, while Kazeshini is trapped and unable to follow them.

Where's he going to attack from?

Behind!

You missed!

I'm not that weak!

Cheat!

*gets distracted by plotbunnies again*
There's more fights than just the Hisagi/Kazeshini one though. Ichigo vs Zangetsu take two is also going on elsewhere.

Where'd you come from?

Look, mum, I can wield my sword one-handed!

Hichigo's too cool for gravity.

I think Ichigo's starting to learn how Byakuya felt that one time.
Renji is also fighting the Zabimaru pair: a fur-covered baboon woman and a cute little snake boy. I love those two, and I think I actually prefer them to the Zabimaru shown during the manga-based Soul Society arc.

Did you have to pull me into your boobs, Monkey?

I know they're not, but Renji looks like he's got freckles right now.

Most people would kill to get so close to Monkey's boobs. Snakey just looks annoyed though.
Hisagi isn't doing so well in his fight. The reason why he hates Kazeshini, a being who is normally a part of his own soul, is the very same reason why he's losing now. Kazeshini's dual blades are fast and deadly, and it looks like it might be the end for Shuuhei...

...until Izuru comes to the rescue.

Shuuhei isn't content to stand back and let his kouhai fight for him...

...but Izuru is determined to defend his sempai.

This really doesn't look like a fair fight.

Shuuhei realises that listening to the former healer when he tells you not to move is probably a good idea...

..but he still tries to stay conscious to watch the fight...

...for all of a couple of seconds.

Kazeshini isn't impressed by his new opponent...

...and tries to intimidate him...

...by running his tongue along a razor sharp blade.

I wonder if Shuuhei would have fallen unconscious so quickly had it been anyone other than his trusted kouhai there.

Izuru learns quickly that Kazeshini's dual scythes can come from any direction...

...and that Kazeshini himself is just as tricky.

Izuru, though, is not so easily tricked, and Kazeshini discovers why you should beware of kidou masters.

Izuru takes Shuuhei to safety, while Kazeshini is trapped and unable to follow them.