My Heart Was Eaten by the Demon Clan from the Start

[Sci-Fi + Wasteland Steampunk Cultivation]

The protagonist's heart is eaten from the start.

Little by little, he gains the memories of a world of future technology.

What era are we living in? Why are you still using a muzzle-loading flintlock?

I hear demons can withstand flintlock fire?

I've got a heavy machine gun!

And if that's not enough, I've got a spirit-powered machine gun that fires twenty rounds a second.