Ancillary : subordinate. Auxiliary, providing additional help or support.
Hermetic : Airtight, impervious to external influence.
Enigmatic : mysterious, relating to or resembling an enigma.
Fulvous : of a dull brownish yellow.
Tawny : fulvous, dull brownish yellow.
Occult : Relating to or dealing with supernatural influences, to conceal or cause to disappear from view.
Abstruse : Difficult to understand.
Impervious : Incapable of being penetrated, incapable of being affected.
Recluse : A person who withdraws from the world to live in solitude. (often for religious purpose or meditation).
Seclusion : the state of being secluded, solitude.