Heyo! I am MarStarBro, I am an Undertale/Fnf music creator. I formally go by either Marstar or Mar.
- Mar’s SoundCloud and YouTube profile.

Mario (full name unknown, most likely Mario Eduardo B. Ballesteros as semi-revealed in a Twitch stream), better known online as MarStarBro (alternatively MarStar or Mar) is a Mexican-American music producer, digital artist, and the lead composer of the now cancelled Friday Night Funkin' mod Vs. Sonic.EXE, created by RightBurstUltra and (prior to July 7, 2022) directed by him and Comgaming_Nz. He started off by making fan-made Undertale songs, but as soon as Friday Night Funkin' modding was mainstream, Mar also decided to make music for mods, starting off with Vs. Sonic.EXE by making Too Slow and Endless. As soon as 2.0 was in the midst of being worked on, Mar also made You Can’t Run (titled off what Scrap Brain was called in the original creepypasta), Triple Trouble (most likely in reference to the Sonic game of the same name), Sunshine (most likely a snippet of Sonic R’s Can You Feel the Sunshine), a remaster to Endless, Faker, and helped UpTaunt with making Sunky’s song Milk.

Asides from his work in Friday Night Funkin' and Undertale, Mario is also a hardcore jazz fusion fan and has debuted in the genre with the instrumental Golden Memory. Along with that, he also made a song called Shooting Stars, featuring the Synthesizer V Studio AI voicebank Kevin on clean vocals, and Nickolas Mendoza, or nik2656, on unclean vocals. He is also a Twitch streamer.