Atari ran two-page magazine ads to launch the four-game series, along with a contest offering up to $150,000 in prizes for the first person to complete the entire saga:
According to the ad copy:
EarthWorld, the first SwordQuest cartridge, is here now. FireWorld is coming soon. WaterWorld and AirWorld will be out by Fall, 1983.
But only the first two made it to market in substantial numbers. WaterWorld did come out, but not in large quantities; it's fairly rare today. And AirWorld is not known to exist in any form beyond preliminary design ideas, nor was the accompanying comic book started, according to Wikipedia.
Oh, and per the same source, the WaterWorld contest was canceled. In the end, only $32,000 in prizes were actually awarded, to the winners of the EarthWorld and FireWorld contests. UPDATE: Correction -- $82,000-plus in prizes were awarded. I wasn't counting the two $25,000-value jewel-encrusted prizes awarded for the first two games. When the whole thing was canceled, Atari gave $15K to each of the previous winners, as there was no chance anyone would win the ultimate prize, and gave $2000 to each of the Waterworld preliminary round winners, however many there were.
All together, now, in our best Christopher Plummer-picking-up-a-few-quick-bucks-with-some-voiceover-work style:
The legend of the Sword of Ultimate Sorcery, and the arduous Quest associated with its recovery... shall remain forever untold.