Shaman perhaps, uses intrinsically nice system from southeast (6)
I believe the answer is:
mystic
'shaman' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for mystic that I've seen before include "Otherworldly" , "One seeking God through contemplation" , "One attaining high levels of spirituality" , "Of hidden or symbolic meaning as in religion" , "One who seeks spiritual union with God" .)