Marshmello is a masked DJ and music producer, and his identity is a closely guarded secret. While the public doesn't know who is behind the mask, the music production company Monstercat owns the Marshmello brand and intellectual property.
This means that Monstercat owns the rights to the Marshmello name, logo, and music. They also control the licensing of the Marshmello brand for merchandise, events, and other commercial ventures.
While the identity of the person behind the mask remains a mystery, Monstercat plays a significant role in the success and management of the Marshmello brand.