They are from the same author, taking place in the same universe with a few other stories.
1. Invincible Mumu (no manhwa currently)
2. Absolute Sword Sense
3. Myst Might Mayhem
4. Nano Machine
5. Descent of the Demon God (no manhwa currently)
Spoilers
Myst Might Mayhem MC is the 1st Heavenly Demon in Nano Machine, yes
I asked that because when I finished reading the translated novel of 'Myst Might Mayhem', there's a side story, where 'nano' mention..
So somehow, i got confused, I thought its a wrong chapter (￣∇￣")
Here, take a look'~
https://novelbin.com/b/myst-might-mayhem/chapter-4989
Was ’myst, might, mayhem’ and 'nano machine' connected story(like prequel, sequel or something)??