Hitogami saying some honestly suspect shit all of a sudden.
He generally hasn't steered Rudeus wrong to date, but this time felt different. Like overtly lying by omission. He was encouraging him to stay and impregnate Pursena and/or Linia, which both seem like a horrible idea given their behavior in the last year. It was almost like he wanted Rudeus to settle down and live out his life doing nothing. Like Hitogami already got what he wanted out of Rudeus (whatever that is) and was just kinda...done with him.
Maybe the new attitude is because Rudeus befriended Nanahoshi? She's a big aberration in the world, and she's making headway on breaking dimensional barriers.
The hint was that Rudeus would regret leaving, while absolutely refusing to reply what or with what magnitude is very suspect. The obvious regret in going to save Zenith before would be failing to reconnect with Sylphie and resolve his ED funk about Eris. Even further, Rujierd telling Rudeus he probably got Eris' intent wrong. So that part was right. But his alternate advice wasn't very compelling this time.
So what's the regret now? Miss the birth of his first born? Sure, that's a medium-big regret, but maybe a pretty small regret in the grand scheme of things.
As much as I kind of disliked Norn, I think she served her purpose here very well. If Rudeus doesn't go, an accomplished mage with some real skill, he'll certainly regret staying behind and making all the others do what he swore to do long ago. Because there really aren't that many people out there as accomplished or versatile as he is now.