okay so we got the 4 corners thing Quincy <---> Shingami & Hollow <---> Human

so that's how he stabilized those Vizards.

- Ichigo go was born with all 4 boundaries Human, Shingami, Quincy & Hollow within his soul thus he was balanced.

- finally now we know why he never returned to SS but how she died seems mysterious.

- Did Aizen purposely kill her off ?

anyways good chapter we finally got some story line development rather than mindless action with blank pages.