After various other efforts, Milarepa returned to Marpa again and was finally accepted as his student.
In forcing Milarepa through these trials, Marpa had actually acted in compassion, as this permitted Milarepa to destroy his proud arrogance or individuality and accompanying bad karma. After the trials, he was ready to fully submit to his teacher.
Milarepa was then left to meditate on his own for 12 years, after which he attained the state of Vajradhara or full enlightenment. From this time he became known as “Milarepa” (meaning great man dressed in cotton clothing).
After this he retired to a cave, where he lived on nettle tea only, from which his skin turned green (as he is depicted). He then became a wandering ascetic.