In Dariusburst, also from Taito, the boss named Dark Helios changes form and appears to be the metal dragon from Syvalion.
Japanese: サイバリオン, Hepburn: Saibarion /wiki/Japanese_language ↩
"Syvalion - Videogame by Taito". The International Arcade Museum. Retrieved 27 December 2012. http://www.arcade-museum.com/game_detail.php?game_id=9991 ↩