There is no dragon in ygret story, because all dragon already move to dragon realm after winterbell serries end. The reason why, is in this story winterbell. Oh, not all dragon move to dragon realm, shuhanan not move yet because he wanna revenge, end up found his son (estio). So, shunanan and estio is the last dragon in human world, after shuhanan and estio go to dragon realm, no dragon left in human world. Then after shuhanan and estio go, start of ygret story, thats why no dragon in ygret
Actually, after the story of estio end, estio and shuhanan back to human world. I don't know if they Will meet, since i do not read ygret (estio promise back in 100 years). In the side story also explained that "the crown prince of rubarzan Will solve the necromancer problem", i don't know if the crown prince is ygret or not. If the crown prince really ygret then, estio and ygret is in same world at that time. Mubien is also alive at that time (since he Didnt severed their contract). Maybe in the novel of ygret ITS explained? Or maybe they meet? IM curious at this too. Since estio find yegret and leave human world has around 100 years time, estio shouldve there when ygret reincarnated as the crown prince

Learning that Egret, Estio and Winterbell being in the same universe was not in my list and especially because it's sad, in Egret I don't think I've ever seen them mention the dragons or maybe I just don't remember