Formation Union

Formation Union was originally released in the 2004 Yu-Gi-Oh! Trading Card Game set Magician's Force. It was designed to support the newly introduced Union monster mechanic, a category of cards that could equip themselves to other monsters to grant stat boosts or special effects. The card was intended to provide players with a way to special summon these Union monsters directly from their hands, bypassing the standard summoning requirements and facilitating faster field presence for machine-based decks.

The card was later reprinted in the 2005 compilation set Dark Revelation Volume 1, which served as a massive anthology release designed to make older, essential cards more accessible to the growing player base. Like many early support traps, its illustration features thematic, industrial imagery consistent with the era's focus on machine-type synergy. While it saw niche play in specific Union-centric strategies during its debut, it remains a nostalgic inclusion for collectors interested in the early evolution of game mechanics.