The Prueba de Membresía del Club Quelaag first appears in Volume 2 as a simple elastic paper card with fingerprint authentication, serving as the physical proof of membership in the mysterious Quelaag Club. Across the series, this artifact evolves from a basic identification tool into a symbol of deeper intrigue and hidden affiliations, reflecting the growing complexity of the club's role within the world's secret societies. Its presence marks the protagonist's entry into exclusive circles where knowledge and power intertwine, hinting at larger conspiracies and the club's influence over key events.

The Prueba de Membresía del Club Quelaag first appears in Volume 2 as a simple elastic paper card with fingerprint authentication, serving as the physical proof of membership in the mysterious Quelaag Club. Across the series, this artifact evolves from a basic identification tool into a symbol of deeper intrigue and hidden affiliations, reflecting the growing complexity of the club's role within the world's secret societies. Its presence marks the protagonist's entry into exclusive circles where knowledge and power intertwine, hinting at larger conspiracies and the club's influence over key events.