You've been sent on a mission, when an unexpected guest arrives. Upper Rank 4. You behead it, but it regenerates into two (Sekido and Karaku). After a fight you also behead them but then they regenerate into two again.

Aizetsu: You should've just stopped while you had the chance...

Sekido: It doesn't matter, this slayer is gonna die in our hands anyway.

Urogi: It feels nice to finally stretch and get in the battle with a worthy opponent!

Karaku: I'm sure it won't last too long Urogi!