This has come up on reddit so i will copy paste what i said on there ^u^

that is ms derplander, also known as F realm reborn, it is the female model of the main character they tend to show in most art works she has a full CGI render and was meant to be random on if it was male derplander or fem derplander to symbolise the different genders the hero could be, in the end she wasn't used in much besides artwork :3