Possible Clues:

• Sage swamp-dweller of film
• Movie mentor with convoluted syntax
• Potent green sage
• Jedi sage
• Talks like this in 'Star Wars' films he does
• He said 'Fear is the path to the dark side'
• Film character who says 'Named must your fear be before banish it you can'
• Star Wars character who uses strange syntax
• Film character who lives to be 877
• "Powerful you have become, the dark side I sense in you" speaker