Reincarnated as Sans twin brother

Grounded

Time skip

Shinzō POV

It has been a few years since I have been in this new alternate universe. I was devastated over the destruction of my old universe but later moved on because there was nothing I could do to fix it. And now I have been living the best years of my life in this universe. I have become the proud parent of two twin boys and a younger son. Since the day after Papyrus asked me all those years ago to be their father.

They have shown me nothing but love and adoration all this time. I did tried to teach them some things that monster parents would teach their kids. But I didn't have to teach them much of anything because they already learned most of that stuff on their own. It has been them who have been doing most of the teaching. They taught me all they know about their world, and their hobbies, and are even sharing their library with me.

I like to stay in our pocket dimension home even more so when Sans made me a lab and my very own work area. At first I didn't go outside for the first few days because I fear the new universe I now lived in will change for the worst because of me. Sans had already told me it happened once mainly when my alternate self was pushed in the core and can sometimes still happen whenever the name Gaster is said outside our home. I feared that there was a chance that this universe would change again if anyone found out about me being a Gaster.

So just like my boys, I wear a Kitsune mask whenever I leave the pocket dimension home and don't use my old name. Papyrus even got me a bunch of beautiful magenta furisodes so I didn't stick out like a sore thumb. But even after weeks later I still had a big fear that the universe would most likely try to use me as a replacement for the old Gaster. But then I learned there was nothing to fear after being dragged out of the house by my kids a few weeks later. And how I can proudly call myself the father of my boys without fear of anything bad happening to us.

It was when I proudly told Grilby that I was their father after Papyrus introduced us together for the first time. That's also the time we came up with a back story of why I wasn't with Papyrus and his brothers from the beginning. My boys told him I was a medic in the war but right before the war ended the camp that I was stationed at was attacked by enemy humans. Later they were told I was M.I.A at the front lines because no one knew if I was dead or not. I finished up the story after them by telling Grilby I was in a coma after being helped by some kind humans that found me. They fixed me up as best as they could but due to my injuries they didn't know if I would ever wake up. When I did I thanked them and traveled home to my children as fast as possible and just made it home a few weeks back.

Grilby and other monsters believed our backstory and welcomed me back with open arms. Some even thanked me for my service at the front lines but that's when something weird happened. Some monsters said I saved their lives on the battlefield and told me how thankful they were for saving them. I had never met them before so I was confused as to why they said I saved them. I must have shown a confused expression and some monsters asked if I did not remember them.

Sans quickly told them due to me being in a coma for so long I had forgotten a lot about the war and some things about the monster empire. Then said we'll all talk again later because we had to prepare dinner before it was too late. Later when we made it home Sans told me the universe must be trying to add me in like we suspected but not in the way we thought it would. It changed but instead of trying to replace me as my alternate self it added me into itself as their father. Because my alternate version never claimed to be their father in any way the universe just made me their father because I said I was.

It was a little scary how the universe did that but over all we were happy about it because that meant that nothing bad would happen if I stay outside and talk to other monsters besides my sons. But I still like to spend most of my time in my lab but I'm always made to leave it at certain times of the day. And when I say leave I mean dragged away from my comfy lab by Papyrus or Mincho. Sometimes they would do it at the same time if I'm being what they describe as difficult. I'm not even allowed to be in my lab when I have to eat or sleep.