Vassago

Vassago is attested within the corpus of European grimoire literature as a named, individuated spirit belonging to the roster of entities a magician may summon and command. The grimoires present him as holding an office within a hierarchical spirit polity (a prince ruling subordinate spirits). Manuscript variants present different counts of his subordinates and slightly different characterizations; one manuscript (Book of the Office of Spirits / Sloane MS 3824) records him under the variant name Usagoo and describes him with angelic language, while the Lesser Key presents him as a Goetic prince ruling legions of spirits.

Grimoire excerpts supplied do not give a detailed, consistent physical description. The Book of the Office of Spirits (Sloane MS 3824) records Usagoo as 'appearing as an angel' and as 'just and true in all his doings,' implying an angelic manifestation in that source. Other manuscript summaries in the Lesser Key do not supply visual particulars. Later modern fiction and games depict varied and creative visualizations (e.g., a winged skull-headed monster in a modern video-game expansion), but those are adaptations outside the primary grimoire descriptions.

In the grimoire tradition Vassago is summoned to tell magicians of past and future events and to locate lost objects (Lesser Key). The Book of the Office of Spirits (Sloane MS 3824) credits Usagoo with powers including inciting the love of women and revealing hidden treasures, and records him as ruling subordinate spirits (manifest counts vary between sources). He functions in ritual contexts as an informant and as a target for containment techniques (e.g., the 'Experiment of Vassago' intended to capture named spirits in crystals). Later fictional sources attribute hostile, combative behaviors, but those are modern creative additions rather than primary-grimoire claims.