"Easy to guess"? So I assume Yama probably already knows who would want to wage war on SS. Since they're Quincies, then Yama might know that not all of them were eradicated.
bleach.wikia defines the Shakonmaku as "The dome-shaped reishi barrier that surrounds Seireitei." in case anyone wondered what it was.
"They can bankai." It SOUNDS like "they can use Bankai", but from what we've seen with Ivan/Ebern, he might mean "they can STEAL bankai". If Yamamoto knows stuff we don't, he might have already known that they were trying stuff with Bankai.
"This shadow only hides the chosen ones." Yay, cryptic. Might have something to do with "True Bloods" that was mentioned earlier, or something.
Ohlook, the ice palace thingy.
"You kidding me, who would bow before someone like you?" Reminds me a LOT of Grimmjow V Ulquiorra.
Oh look, an arm was cut off. Was it Zam that had the list?
So...yeah. Retreat. Probably going to focus on Ichigo's reaction to Ivan, and him telling Ishida/Chad/Orihime(/Urahara?).