Vepar, also known as Separ or Vephar, is the 42nd demon listed in the Ars Goetia. He is a Great Duke of Hell with 29 legions of demons under his control.
He governs the waters and guides armoured ships laden with ammunition and weapons; he can also make, if requested, the sea rough and stormy, and to appear full of ships. Vepar can make men die in three days by putrefying sores and wounds, causing worms to breed in them, but if requested by the conjurer he can heal them immediately.
Vepar is depicted as a mermaid. Despite this, he is always described with male pronouns, although this may be due to the fact that words like "merman" were uncommon or not in use when Vepar was first described.