Quest guitars/basses were made for the US company MTI (formerly known as Merson and Unicord) at the Matsumoku factory, in the last years before its closing down. The line was launched as "Quest by Vantage" and seems to have been developed in-house as a follow-up or sister brand, as Vantage itself (an earlier MTI/Matsumoku collaboration) was transferred to Samick in Korea (1985). A Canadian distributor, Jam Industries, also provided some input. The Quest "Black Magic" bass had the model number SB-108 and was styled in accordance with a brief mid-'80s fad for all-black basses with red binding or accents (viz. Takamine and Washburn).
A design and production company named Quest International currently exists, producing MD and Landscape brand instruments as well as acting as the business agent for Gotoh hardware. The founder/owner apparently was Matsumoku's head of R&D in the past. http://www.quest-md.com/en/index.html