Vtb is the abbreviation of Virtual YouTuber(VTuber), which is often active in foreign live broadcast platforms, meaning virtual anchor. Traditional vtb generally refers to the UP of virtual role-playing synthesized by computer animation, and then the anchor with virtual role avatar appears by real users.
Virtual anchor in a broad sense refers to the up owner who contributes to the video website with a virtual image, and there is no restriction on whether to set up a virtual person. According to this standard, Ami Yamato can be regarded as the first virtual YouTuber in the world. But it just changed its image into an animated image, with a real identity behind it, which can be considered as a generalized virtual YouTuber.