Danji Momoyama, born Nadatsugu Minae, is a 23-year-old with maroon hair, light grey eyes, and a tall, muscular build. He first led Team Blackout, a group united through cardfighting at an abandoned amusement park, though it was later revealed he succeeded the original founder Ruka Miyako as their second leader. During his command, he secured 20 consecutive cardfight victories and mentored members like Yu-yu Kondo.

He departed Team Blackout to join Team Daybreak, driven by a desire to reconnect with Mirei Minae, who shares a significant personal bond with him. This shift ignited conflicts, including Team Daybreak burning rivals' banners, but Danji reconciled with his former teammates during crises like the Uniformers threat.

As a cardfighter, he wields a Dark States deck featuring the avatar "Violence" Bruce, battling with a hot-blooded, passionate style. Outside the arena, he works diverse jobs: botanist, kindergarten teacher, construction worker, and priest. His leisure includes savoring the Big Kani-Kani Parfait at Princess Time Cafe.

His journey transitions from leadership to support, navigating clashes between old and new alliances while pursuing motives tied to Mirei. After reconciling with Team Blackout, he stays with Team Daybreak yet shields his former team in later challenges.