Board Thread:General Discussion/@comment-67.166.53.79-20170418213555/@comment-93.16.135.125-20170419153232

Waver's adult version has been known for a decade, I think it was in the first Character Material along with  stuff like   Proto Saber, ORT and Slash Emperor, he's a teacher, he took over the name El-Melloi as Lord El-Melloi II   (Kayneth's sister blamed Waver for Kayneth's death so she forced that on him), he tends to find unique and powerful students, Rin also studies under him when she's there. There's more, like dismantling the Greater Grail in non-Heaven's Feel routes, but I'm pretty sure you can find all that in his page in this Wiki.