I haven't seen the latest bleach 20 episodes but still, it has something to do with the winter war. Byakuya is probably still at Aizen's Hollow fest and battling some wimpy arrancar.
Oh yeah, saw that opening a few weeks ago. Lame. Rukia? Come on, she's already a main character and now this? u.u Kubo-sensei, you're overdoing it.
Kisuke-kun was the 12th division taichou along with Hiyori-san as the vice.
And then he had to rush back to the human world to do something and before he escaped, he got Mayuri to fill in for him. :]