Possible Clues:

• Ancient Jewish sect
• Possible Dead Sea Scrolls writer (hidden in "boundless energy")
• Tired and bored
• Ancient Jew from German city quarter
• Old religious type takes crucial lead from nature
• One of those whose library was potted at Qmran
• German city's Eastern ascetic
• By the sound of it, that's a bit of play for the sect
• Sect sounds like a bit of play
• Early sect member