In the case of an enlightened being, rebirths are taken consciously, motivated by a desire to benefit all living beings and made possible by the depth and clarity of an individual's realization. The first such reincarnation (tulku) was recognized in thirteenth-century Tibet. His name was the Gyalwa Karmapa, "The Victorious One of Enlightened Activity." Thereafter, he continued to return, generation after generation, until the present seventeenth Karmapa. The Karmapa is said to embody the activity of all the buddhas of the past, present, and future. Citing ancient texts, traditional histories trace his lives back for eons and continue it forward into the distant future.
"His Holiness the Gyalwa Karmapa holds, teaches, and inspires the lineage of the Kagyu order, which is known for its meditative practices, its focus on retreat, and the many realized masters it has produced.
Like the Dalai Lama, the Karmapa is regarded as an embodiment of compassion, represented by the deity Chenrezik.
The sole purpose of the Karmapa's incarnation is to lead living beings from the suffering of samsara into freedom- the realization of mind's deepest, pure nature. This full awakening, or enlightenment, is possible for every living being who sincerely engages in practice."
From - Music in the Sky: The Life, Art & Teachings of the 17th Karmapa, Ogyen Trinley Dorje Copyright (c) 2003 Michele Martin