"Escape to Salvation" - "Magnificent Retreat" [Campaign 4, Mission 4]

Take a look at the skills and abilities wheel. Education - magic attraction - sorceress reward - mentorship. Mentorship is when a hero possessing this skill ("mentor") meets another friendly hero, and the latter receives experience equal to the amount needed to bring their experience level to one-fourth of the "mentor's" experience (this only works if the hero being met has less experience). Zehir had 31, and the alien now has 28)).