### Clue: Spirits initially not seen — they may be here (5)
### Answer: HADES 
 ### Explanation: Definition: they may be here
 "shades"(the spirits of dead people/ghosts, in literary form) **minus its 1st letter**(initially not seen).
Defn: …/where spirits and ghosts may be found.
… as depicted by Jan Brueghel the Elder.