Complex sentence: The first game in the Famicom-based RPG series was released in 1986, and would eventually sell 1.5 million copies in Japan, establishing "Dragon Quest" as the company's most profitable franchise.
Split into simpler sentences: The first game in the Famicom-based RPG series was released in 1986. The game would eventually sell 1.5 million copies in Japan and establish the company's most profitable franchise.