Ismenios is a human wizard who adventured with Arvizu circa 3950 BEC. He later studied with dragons and through that discipleship, became a Half-Dragon himself, and later, after his death in a battle against the Torrasque, a DemiGod. He has a very close friendship to Arvizu.
He is responsible for the cataloging and creating many of the spells known in the common era. His writings on the Arcane are required reading in Mezzobodan for all levels of study.
He is commonly cited as the most powerful mortal wizard to ever live, a title Malick of Mezzobodan covets.