As young men both Amadeus and Magnus studied under the same master many years ago. As they grew more powerful studying elemental and planar magics they were commonly set aside by their master as he corresponded with a wide network of contacts and participated in secretive meetings. This incensed the young Magnus, leading at times to bitter words and rash actions.
Eventually, Amadeus alone was called into their master’s tower where he was told about their master’s connection to the Order of the White Lotus, starting his long association with them. Shortly after this meeting their master sacrificed himself to prevent a coup of Riva led by members of the Cult of Nerull, falling to Shadow Magic even as he worked his final spell.
After seeing this, Amadeus devoted his life to Ioun, Goddess of Knowledge and rumoured founder of the Order of the White Lotus. Instead Magnus made an enemy of death itself, forever seeking to hold it at bay through sheer power.