Bicorn/Extra

Extra

Trivia

Unicorns and bicorns do not dislike each other. Bicorns tend to think about how great a unicorn they see would be as a bicorn, while a unicorn seeing a bicorn may feel curious about becoming a bicorn. However, bicorns will not change unicorns indiscriminately. Just as when adding harem members, they consider the relationship status of the unicorn, who she is in love with, etc. and would not change a happily married unicorn (source: Patreon Q and A).
Bicorn is first mentioned in unicorn's updated profile from MGE1, more than a year before the official profile.
The bicorn profile art depict the same individual unicorn after she has evolved/transformed. (source: Enty info article for the making of the phantom profile).