Treason? I’m Just Collecting a Debt, So How Did They All Become Cauldrons?

[The protagonist is a bit of a prankster + National Fate + 10,000% interest + ruthless + multiple female leads + extreme contrasts]

Cavern-dwelling aliens have descended, leaving China to face the crisis alone.

Foreign enemies lie in wait, while a traitor within hollows us out. The vicious childhood friend I once personally supported has secretly colluded with an enemy nation during the National Fate trials, willingly becoming a collaborator!

What a joke. She doesn't know I've already awakened the [Ten-Thousandfold Repayment System], which lets me lend out anything, even all kinds of “Systems.”

Those who default owe ten thousand times more. Those who refuse to honor their agreements lose everything!

In these chaotic times, evil must be punished. This enormous debt of karma will leave her as the lowliest furnace, repaying me for the rest of her life.

And the male collaborator who helped her?

Ding! The Super Cuckold System has been unlocked.

He's already lost himself in his own art...

Later

The cool, beautiful top student, desperate to pay for her mother's medical treatment, can't repay her debt and begs me through tear-filled eyes to take everything she has;

The righteous senior with a huge debt can't fulfill her agreement, so she puts on a contract seal and becomes my personal debt-slave;

Even the aloof, white-haired immortal and the cold Empress who wields great power, after falling into debt, offer their bodies as payment...

Gu Chen looked at the row of peerless beauties kneeling before him and spread his hands helplessly:

“I got where I am today through hard work and sweat.”

“Whose sweat it was... doesn't matter. I just want to collect a debt.”

Those who harbor disloyal intentions will be shown no mercy! No one gets to dodge what they owe China!

And as for those collaborators... are there even any enemy nations left in this world?