Ophiel is one of the Olympic governors named in the Arbatel, a work of early modern magic.
Mercury and fourteen provinces
Aphorism 16 assigns Ophiel fourteen visible provinces. Aphorism 17 associates this spirit with the affairs of Mercury and attributes a hundred thousand legions to its command.
The latter passage also claims that Ophiel gives familiar spirits and teaches all arts. Its account includes a claim concerning the transformation of quicksilver into the Philosopher’s Stone. The Arbatel presents these as powers of its Mercury-associated governor.
Source
Arbatel, aphorisms 16–17, Joseph H. Peterson’s digital edition.