Transmigrated as a Cannon-Fodder Master, I Get Clung to by My Mad Disciple Night After Night

[Female lead transmigrates into a book + male lead is dangerously unhinged + System + immortal-cultivation master and disciple + growing together]

[Unhinged, scheming tea-green male disciple × cannon-fodder villainess master]

After I transmigrate into a male-oriented novel, the System gives me two choices:

A: Follow the plot and mistreat Ling Wuwang, then wait for him to become the Demon Lord and turn me into a human chopping block.

B: Defy the System and get electrocuted into an idiot right now.

I choose C: Raise Ling Wuwang to be a fine, upstanding young man!

I take the attacks meant for him, teach him to cultivate both immortal and demonic arts, but he gradually strays from the script, and the way he looks at me grows more and more unsettling.

So I promptly fake my death and run away!

But when he tramples the Demon Realm to find me and prepares to slaughter the entire cultivation world, I'm panicking, and so is the System.

[Warning: Core plot has deviated severely! Host, please correct course immediately!]

But how am I supposed to fix this?!

Then Ling Wuwang discovers that I faked my death and learns the truth about the System.

He locks me in his arms and murmurs with a soft laugh:

“Master, tell me, is this world...”

“...a cage you wrote for me...”

“...or a nest I built for you?”

The male lead is a bright, sunny young man at first, then becomes a dark, scheming, dangerously unhinged man. The female lead reforms the male protagonist of a male-oriented novel. One-on-one romance, and they are each other's only partners.