The Pangolin Boss Summon is old, even for Boss Summons. The way he speaks about the Sage is almost familiar, and could easily be interpreted to mean that he knew the Sage, personally.
Granted, it could just be grandstanding, but Cannai is several centuries old and it's only been 1080-1090 years since the Sage alive. So I imagine that there are at least a few Boss Summons old enough to remember the Sage.
Anywho, point being, we could have Keiko summon the Pangolin Boss via Noburi's chakra transfer as an intimidation/social manipulation thing to tell stories of Ui, personally.
...of course, the Pangolin Boss might not be suited towards social warfare, and personal stories about Ui might not go over will with the Isanites. Something something, never meet your heroes, something something, if Jesus would be reviled by his own religious institutions.
Edit: although, "institutions" are what we're trying to undermine via the hearts and minds of the people (even if the eventual endgoal will probably be Azai's head on a platter). So it's still a good idea, provided that we can find a Pangolin old enough to have known Ui and also skilled enough in social combat to twist/frame/tell their memories in such a way that they help our standing.
