Tower of the Time Wizard

From the introduction:

Despite having the rather silly title of time wizard, Naven Mag was a well-respected and rather famous spellcaster. Early in her career, she made a major discovery, parallel time casting. This finding allowed chronomancers to effectively cast two spells at once. The rest of Naven’s career was spent chasing the next big discovery, but she was never able to match her first breakthrough. It was this pursuit that led to her death.