"This will be very interseting"
Gaster is the former Royal Scientist before Alphys
Past Gaster- Gaster was so focused on his work but also made sure to take care of his children, he had some of his struggles being with the Core and DT extractor in which produced stress at times. He was a very funny guy who was serious at times awesome to work with.
Void Gaster- Gaster became more into a state of where his goal was to escape the void no matter the choices he made, he was more interested into his experiments more than before. he became kinda evil after falling into the Core