Little Mushroom 小蘑菇 - Chapter 36: "You Two Have a Great Relationship"

A Federation Colonel with abnormal thoughts was locked in a dark room and met a little looney.

“Your whole body emits a scent that I dread (covet) and fear (desire).”

A frigid Colonel X little looney roommate: A sweet story of interstellar travel

- Description from Novelupdates

“Did you just marry the richest man in the country… by accident? How does that even happen?”Delphinia sighed dramatically. “I know, I’m such an overachiever. But it’s easy, really. Step one: drink too much. Step two: find the perfect man. Step three: say ‘I do’ before he realizes I’m a walking disaster.”“And the revenge?”She raised her glass. “Served cold, with a diamond bigger than my ex’s ego.”—After years trapped in a loveless, abusive marriage, Delphinia had one plan: leave her toxic past behind and never look back. But freedom isn’t as sweet as she’d hoped. With no family to turn to and no place to go, she crashes with her best friend…only to end up at a party where one too many drinks lead to one tiny (accidental) marriage to Evander Walton.Handsome, rich, and absolutely off-limits, Evander is everything Delphinia thought she’d never have. And he has just one condition if she wants to break things off: she’ll have to pay him back…for the huge diamond ring she barely remembers accepting. Broke and in no position to negotiate, she’s got no choice but to play along with her accidental husband and the lavish life that comes with him.Now she’s living in luxury, holding her head high, and plotting the sweetest revenge against the ex who tried to ruin her. Because if there’s one thing Delphinia knows, it’s that payback is best served in designer heels.

To save a doomed fantasy world, I killed the main characters, then destroyed the game world, and fell into another timeline as the academy's top seat and rival to the protagonist.Now, I'm trying to save the world and steer it towards a better ending…But I'm the final boss.

Callius von Jervain.

A character who dies no matter what he does. A character who falls into a forced choice route where he can only die, no matter his choices up to that point. However, there is a single route where the character can live and play the game.

And I have to carve out that route somehow.

Because I’ve become Callius von Jervain in the game.