Ren Suzugamori, a central figure in Cardfight!! Vanguard, evolves significantly across multiple series. Initially the main antagonist in the first season, PSYqualia addiction fuels a controlling and sadistic demeanor, driving his manipulation of Aichi Sendou and intense rivalry with Toshiki Kai. As national champion and leader of Team Foo Fighter AL4, he wields a Shadow Paladin deck focused on defensive tactics and sacrificing units for power, using PSYqualia to predict outcomes and dominate opponents. His timid childhood, marked by an abusive father, shifted towards power obsession after discovering Vanguard and awakening PSYqualia.

Defeated by Aichi in the national finals, Majesty Lord Blaster drains Ren's PSYqualia, reverting him to his original cheerful and friendly personality. He becomes more relaxed, frequently engaging in pranks like telling ghost stories or briefly pretending to revert. Despite this change, he retains intensity during cardfights, especially concerning close friends or Vanguard matters. In later arcs like Asia Circuit, he adopts a Gold Paladin deck after his Shadow Paladins are sealed, eventually returning to Shadow Paladins with the Revenger sub-clan. His PSYqualia occasionally resurfaces, reignited during a Seoul Stage match by Takuto Tatsunagi.

During the High School Arc Cont., Ren captains Fukuhara Academy's Vanguard Club, competing in the Vanguard Koshien. Facing Aichi in the finals' first match triggers his PSYqualia, granting a glimpse of "the destiny he had lost" and prompting reflection on his past and the path not taken. This moment highlights the balance between his lighter persona and lingering echoes of his former self. His journey spans obsessive ambition, redemption, and reconciliation, maintaining his skill as a cardfighter while evolving into a more supportive, team-oriented figure.