To his followers, he is the 17th Karmapa — the leader of the Karma Kagyu school of Tibetan Buddhism and the latest in a line of reincarnated Tibetan teachers, or lamas, stretching back to the 12th century. He’s been training for that role since the age of seven, when other important lamas recognized him as the reincarnation of the 16th Karmapa, who died in Illinois in 1981.