It's a good day to be black and sexy

Seohyeon was a B class guide.

She wasn't good enough.

Her family was very cold, but she managed to marry up.

Sadly her S-Class Esper husband, Ciel, lost control. His powers burned down an entire street. Seohyeon attempted to save him. She died in the process, and it's implied that they both died because yeah....Seohyeon wasn't strong enough. The gap in their abilities was too big.

Right before her death Seohyeon decides to let go of her love for Ciel. She did truly love him, but his love in return didn't make her happy. Their mismatched B and S ranks made her life a challenge as well. She rushed in to save him, sure, but at the bitter end she admits that he wasn't for her.

Their marriage wasn't making her happy.

Irene de Closhe has a loving family. Seohyeon reincarnated, but she has let go of the past in a fairly healthy way. She appreciates her new life and the love she has. She's happy she doesn't have to worry about being a Guide as well.

Her peaceful fate changes.

She resists for a while, but her husband died with her and he's also part of her new life as Irene.

Irene de Closhe runs from the mad Ciel de Leopart. He's even more handsome and powerful in this world! His boss is the Crown Prince.

Irene de Closhe cannot hide for long.

He is desperate to get her back.

She did make quite an impression. She threw herself into the flames to try and save him. He did love his wife in both universes. However, their first life together was infected with classism/different love languages and a lack of communication.

Ciel de Leopart is very clear.

VERY.

Irene de Closhe still has her guiding powers from her previous life, and it looks like Ciel still needs them.

Can she let go of her bitterness about their previous rocky marriage? He's more loyal than ever. More vocal than ever. He's mad for her, but does she even want that?

The former couple reincarnated into a novel. Ciel de Leopart and Irene de Closhe are both side characters. Ciel de Leopart is an important secondary male lead and Irene de Closhe was supposed to be a normal woman. Not a Guide with special powers.

Unfortunately I heard that the original heroine of this novel is evil, which will be quite boring in this setting. Let me explain. Irene de Closhe and Ciel de Leopart WERE the disadvantaged characters, but they have superpowers. There's no tension at all.