Possible Clues:

• Ghost or spectral appartition
• The artist in with this shade
• Artist enters with something insubstantial
• Ghost, spectral apparition
• Apparition, phantom, spirit
• Scottish battlefield's rumoured to have a ghost
• First person in cape to see apparition
• Wight is island around which there's anger
• Ghostly apparition
• “The Water-____ ascended thrice / And gave his doleful warning” (Wordsworth)