This is actually the prequel of Records of Unusual Creature which is available here in webnovel (idk why the sequel is available first than the prequel tho).
Description from novel updates:
This isn’t the struggle of an empire, nor the tempest of another world, and definitely not a cultivation story. This is actually a super serious (not really), super hard sci-fi novel about saving the world. Take what I’m saying seriously.(Don’t)
Okay, it’s really just a bunch of slippery leaders and their deceptive emperor having a fun time saving the world everyday.
An unmotivated otaku is transformed into the Emperor of an ancient intergalactic magic sci-fi empire, and with the aura of a stay-at-home dad, he is similar to an uncle who adopts an army of lolis. This is the hilarious story of an otaku and his freeloading army that appeared out of nowhere. Once again, this is a super serious story. This is a super-ultra-serious sci-fi story.