Board Thread:General Discussion/@comment-5413572-20170219072514/@comment-13682699-20170225203049

It seems fairly like as Gaster has knowledge of humans being the previous royal scientist and has likely studied the barrier to try to break it. However, I don't think its because he lacked a save point that he was lost.

I believe all living beings have a save point sometime in their life that they could return to if they loaded, but such access to use those points is limited to whoever has sufficient/most determination. Because monsters in general lack enough determination to access those points, if someone were to try to force it to happen without the proper determination (by using the core for example), their soul would instantly shatter as they don't possess enough determination to survive a load to the save point. Because the soul shatters along the way to the save point, its simply lost amongst time-space in between the possibilities of the world. Since the soul didn't make it back to the save point, that save point simply collapses as the person who tried to use it simply exists outside of time-space now and the world is "rewritten" as if the person never existed at all. And because they "don't exist" when outside the world, the rules of life and death no longer hold any meaning to them, so they are forever trapped in limbo forced to watch the endless possibilities of a world where they don't exist anymore.

Its probably why only certain timelines allow you to even get a glimpse of him as save/loading is the only way to indirectly interact with him as the actions allow you to briefly cross such areas to get to your destination. You can see him if you mess with the files of the world and make it so that you do meet him.

I also think that if someone has enough determination to use save/loads like Flowey, that their determination allows their essence to travel alongside the more determination person to the time of the latter's save point, giving them perfect clarity of the previous timeline.