The Hated Chief's Revenge and Captive Love

Original blurb:

[Black-turned-white fake S-Class Sentinel x white-turned-black fake sunshine Guide]

Kai was reincarnated into a poor Muggle family, but happened to be born with a handsome face, a strong body, and a big heart. Desperate to escape the label of "stinking, low-class beggar," he used every means at his disposal to sneak aboard a luxury cruise ship for the nobility. There, he fell in love at first sight with a young Guide.

A murder took place aboard the cruise ship. Kai saved the young Guide, but was arrested as a fugitive and branded a "Dark Sentinel."

*

Me? A Dark Sentinel?

Is that for real?

Kai was stunned, but quickly embraced the identity. He'd finally made it into Sentinel society!

He looked toward the witness stand, where the frail young Guide wore a cold, smug expression.

Kai: He's different from other Guides. He's so special.

*

After entering the Sentinel Academy, Kai's homeroom instructor told him, "Because of the risks posed by Dark Sentinels, you must complete your coursework with a team to prove that you're stable."

The moment Kai stepped into his dorm room, his eyes widened in shock. Why did his roommate look so much like his first love, the Guide?

Mie: Hehe, no wonder you're a Dark Sentinel. You're hilarious.

Before long, his roommate Mie's nasty personality shattered Kai's rose-colored glasses.

Kai: You can't be my teammate and help the former top student's little brother pass at the same time.

Kai: Are you choosing him or me?

Mie: Oh, big brother, I want both...

Kai: Get lost. No, come back! You can only choose me as your teammate!

Mie: So should I go or come back? Give me a clear answer.

Kai: Choose me. That's it.

*

After graduating, Kai went from being a murder suspect to practically becoming the leader of the Sentinels in the enforcement division.

Kai: I want everything there is to know about this Guide by the end of the day.

Colleague: I found him. He's the former top student's Guide. He went into hiding and disappeared later on. I heard he was so badly injured the day they bonded that he couldn't get out of bed. Poor thing. Should I arrange a meeting for you two?

Kai: Immediately.

*

When they met:

Kai: Wait, isn't this my freaking roommate?

Mie, who had come to apply to be his adjutant: What the hell?

For the recipient's perspective, see Raising Six Crazy Sentinel-Guide Pairs with Murder Mysteries.

The timelines differ slightly. You can think of it as Mie's memories, the recipient's, having been altered.

Theme: No amount of scheming can beat sincerity