@belgopolac well, broconish vibe aside, when he asked the goddesses to keep an eye on or make sure she is ok without him, after he left they revealed confusion about that because according to their sources he doesn't have a sister.
This chapter we got some ominous scribble on the floor and "I'm coming to where you are". Then the goddess tells our boy his sister went hiking on my Fuji. By ordinary human perception, all she should know about oniichan's location is "dead". There's cheaper and more efficient ways to reach the land of the dead, unless there is folklore about mt Fuji that I don't know connecting it to heavenly realms.
So either the goddess lied about her climbing Fuji, or she somehow KNOWS her bro has been isekai'd and has a plan to get there.
The fact that this is juxtaposed with info about the seal on the demon Lord coming undone is also troubling, even if it might be unrelated. Do you recall what chapter had Haru sharing her history with the demon Lord? Because just based on this chapter it doesn't sound like HER demon Lord acquaintance is currently sealed away.