What did askin mean by saying "Future Emperor" looking at jugram?

if quincy succeed, ywach will be SK and Uryu will be the successor( future emperor) then why is askin calling jugram that? is that sarcasm or he knows about jugram sharing ywach's powers(day and night). also, jugram is so hard to read, and kubo keeps drawing that same side eye panel everywhere, i dont understand why and i dont understand what it means. pls explain somebody. also does askin or jugram know uryu negating aushwhelen when ywach says he's the last quincy

https://preview.redd.it/csdzkwa8g3ge1.png?width=571&format=png&auto=webp&s=7146b0464dcd768ed0c40ca23de199dd63f6685b