Possible Clues:

• The Spanish start to move away from Swiss cheese — that's the spirit
• At the Louvre, the staff opening late brought up key
• Got the eel twisted in mind to a huge extent
• 'So powerful, mind the end of it (9)'
• Fundamental or essential
• Nature spirit
• Supernatural entity
• Basic part of electric heater's aluminium
• Hint given to a learner? That's natural
• Cooked eel with crackers is basic