According to The Dictionary of Demons (Michelle Belanger), Focalor “has power over the wind and seas. He can overturn ships of war and drown men in the waters.” Despite this ability, however, apparently Focalor can also be “commanded to leave people unharmed and he is said to willingly consent to this request.”
A duke of hell, Focalor commands 30 legions of demons (A Dictionary of Angels, Including the Fallen Angels – Gustav Davidson). When summoned, he appears as a man with gryphon wings.
Focalor is unique among demons in that he hopes to one day return to Heaven.