Shun's been doing a fair bit about the cultists, so he probably would have passed on to Amaterasu information about the attempt at cursing her shrine that the mission with Zelda and Hibiki pulled up, the connection between the charm incidents (and that the ones behind the initial attack that had them, the department store, had been humans acting under orders of someone who'd only left a postcard of thanks as hint that they'd been there, so potentially cultists themselves), and the bits and pieces he's learnt about the cult spells on various missions, where they seem to be using summoning or empowering spells of some kind that kill off plant life in the area and attract ayakashi (though he's also passed this information on to Suijin previously, so she may already know it).
He also would have mentioned fighting Sotero but considering it highly unlikely he was actually defeated, since Sotero jumped into the volcano to escape them before anyone could land a decisive hit.