Many VTubers, particularly those in the "idol" space, cultivate a persona that is relatable, engaging, and often flirty or romantic with their audience. This can be intentional, to appeal to the "girlfriend/boyfriend experience" (GFE/BFE), or simply a natural part of their character. This is the state where they are "single" in the eyes of the persona and the fans who have a parasocial attachment.
The person behind the avatar, however, is a real human being with a private life. They may be in a committed relationship, married, or single. This is the state where they are "in a relationship."
The paradox holds as long as the two states—the persona's and the person's—do not overlap. The moment the audience "observes" or discovers the real-life relationship, the single persona collapses, and the potential for drama and fan backlash arises.
Why This Dynamic Exists
Separation of Character and Person: The fundamental principle of VTubing is the separation of the character (the VTuber persona) from the person (the content creator). The character can have a fictional backstory, personality, and even relationships that are distinct from the creator's real life. This allows the creator to protect their privacy while still building a deep, emotional connection with their audience.
Parasocial Relationships: A significant part of a VTuber's success is built on parasocial relationships, where viewers feel a one-sided sense of intimacy and connection with the streamer. For some fans, the belief that the VTuber is "available" is a key part of the fantasy and the core of vtubing.
Industry Standards and "Idol" Culture: The VTuber scene, especially the larger corporate agencies, is heavily influenced by the Japanese idol industry. In this culture, idols often have strict rules against dating to maintain the fantasy of being an unattainable, perfect partner for their fans. While many VTuber companies are more relaxed than traditional idol agencies, the expectation of being "available" still lingers for some audiences.
The Key to Success: Maintaining the Boundary
As you pointed out, the critical factor is whether the VTuber "links that to the character." The most successful and long-lasting VTubers navigate this by:
Maintaining the Kayfabe: The VTuber keeps their private life completely separate from their on-stream persona. They don't mention their real-life partner, and their content is focused entirely on the fictional world of their character. This allows fans to continue engaging with the single persona.
Clear Communication and Boundaries: Some VTubers are upfront from the start about having a partner. While this may alienate some fans, it establishes clear boundaries and attracts an audience that respects the person behind the avatar. Other VTubers are more subtle, with a rule like "no talk about my personal life."
Managing Fan Expectations: The most challenging aspect is managing the expectations of fans who feel betrayed when the reality of a relationship is revealed. This often happens not because of the relationship itself, but because fans feel they were deceived or that the parasocial bond was a lie. This is why scandals involving "secret boyfriends" can be so damaging.