#he wasn't interested in ruling over it anymore or even supporting the not Lycaon Emperor

[randomnameless]

I read a lot of your posts basically saying Wilheim left Adrestia after his son's death, but is it only your headcanon or somewhere in the games?

I usually try (but then i often forget) to tag the headcanon stuff with "fodlan au" or "fodlan hc", but as for Willy leaving Adrestia, it's basically in Rhea's big "did you know Wilhelm was the greatest Emperor who ever Emperor'd" infodump speech she hits Barney and Cyril with at the end of Nopes' Nabatean paralogue!

Finally, Nemesis—the leader of the opposing forces— was defeated at the Battle of Tailtean. Having achieved his chief ambition, Great Emperor Wilhelm ceded the throne to his son, Lycaon.

Nemesis died, apparently this was Willy's ambition (uh...) and after Tailtean he gave his throne to his kid, Lycaon.

Wilhelm continued to assist Lycaon in battle.

apparently they were still fighting? JP line is this "その後もヴィルヘルムは、リュカイオンの 後見として戦場に立ち続けましたが……"

But from what I can roughly understand, Willy is still around to support and help Lycaon when he has to fight.

Important thing to note : When Lycaon is Emperor, Wilhelm is still around to "assist" him.

But Lycaon perished at a young age, and Wilhelm soon retreated into the background.

Lycaon "perished" and Willy... retreats in the background. He is not around anymore when Lycaon disappears.

JP wise we have this : リュカイオンの早世によりヴィルヘルムも 役目を終え、表舞台から身を引きました。

Again, from what I understand, it's roughly the same save that the "and Wilhelm soon retreated into the background" is more like something like "so Willy retreated into the background" : Lycaon's death means the end of Willy's role, even if we know there was a successor (the Empress who dueled an Aegir for the throne!).

Other important thing to note then : When Lycaon is no more, Wilhelm fades in the background

He relinquished this shield to Seiros, and together they returned it to Indech's workshop.

We know at least after bailing out of Adrestia he and Rhea were still hanging out and they returned Seteth's shield to Indech's hamlet, what happened to him afterwards, we don't know.

-> When Lycaon is no more, Wilhelm doesn't assist the new Emperor/Empress like he did for his son. He fades in the background. He meets Seiros and they travel again.

That's the canon.

If the order of events is a bit muddled (did he say fig to Adrestia before or after returning Seteth's shield?), fact remains that he was willing to assist and support his son - a callback to the Rodrigue-Felix duo from this route? - but refused to do the same for the Emperor(s) following Lycaon and "faded" away.