The 3rd spirit is Vassago
A good-natured old man with angel wings.
Name: Vassago
Common aliases: Usagoo
Sign and placement: 20-30 ARIES (day)
Direction: Unstated
Rank: Prince
Metal and planet: Tin, Jupiter
Legions: 26 (20)
The third spirit is Vassago, a Prince. He is good-natured, like Agares. His office is to declare all things past, present, and future, as well as to find things that have been hidden or lost. He presides over twenty-six legions of spirits. - Campbell's Of the Arte Goetia
The Third spirit is a mighty prince, being of ye same nature as Agares, he is called Vassago, This spirit is of a good nature, & his office is to declare things past and to come, and to discover all things hidden or lost &c: he governeth 26 Legions of spirits. - Goetia
Usagoo, magnus petis [likely magnus princeps], he appeareth like an angel, and is just and true in all his doings, he giveth the love of women and telleth of hid treasures and hath under him 20 legions. - The Offices of Spirits
Notes:
There will be an additional "3rd" spirit after this as Vassago does not appear in Weir's Pseudomonarchia Daemonum. There is an entry for "Usagoo" in The Offices of Spirits which is comparable but lists an alternate number of legions.
The 'V' in Vassago may thus be pronounced like 'W,' in the Latin style, as the Latin V was basically an easily-carveable form of 'U.' (A similar pronunciation relationship exists between the English 'J' and the Latin 'I.') You would end up with "ooahsahgoh."
"Of a good nature" means friendly in interactions, it's not a reference to spiritual alignment.
