Disclaimer: I don't own this novel/manga/anime or its characters. Or anything.
A little summary on some details: Since this happens after Volume 9, there are some characters that don't appear on the anime nor manga. I will give small summaries on each one on their respective chapter.
SPOILERS: Diablo and his companions received a house for saving the city, so it's like this, one room for Diablo, another for Shera and Rem, and another for Krem and Eldegart. They don't live at the inn anymore, the house is part of the inn though.
Chapter 1 - Shera
"Hey Diablo! How are you doing? You look more serious than usual."
She was alone in her room, in a rare moment without taking care of Krem.
Waving her hand while smiling widely as soon as she saw him, was Shera, the big-breasted elf princess. Though she was a bit(a lot) of dunce, she could be unexpectedly sharp sometimes, such as realizing that Diablo was resolute in finishing this 'trail' that she didn't even know existed.
"I'm always serious."
"Hm? I guess so but... How can I say? You look more resolved than normal?"
(Is she and idiot or not? Sometimes I have trouble deciding.)
"Leaving that aside, I have something to talk with you. It's urgent."
"Oh. Should I call Rem too?"
"No, for now I have to speak with you alone."
"Okay then. We don't really spend much time alone. We're normally always with Rem."
(...I guess huh. It does feel strange not to call Rem too. But I must do it. I have to deal with them one by one. I'll explain it carefully and have them accept it, both the ritual and the "unfaithfulness".)
"I dislike beating around the boat, so I will be blunt. Shera, I want to make our marriage 'real'."
"Real? But aren't we already married Diablo?"
"...Yes, but that's not what I meant. I..."
Explanation going on... bla bla bla
"...and that's about it."
"I see... So Diablo wants more wives?"
"...Shera, I already spent more time than I expected to explaining in a way that you could understand. It's not like I 'want to' but I need to."
"I think it's ok then?"
"...Eh?"
"I mean, it's Diablo we are talking about, right? If you say you need to, then it must be right. I also don't think you would neglect me and Rem. I trust Diablo, after all!"
"..."
(I guess it was easier than I thought. Maybe I underestimated her trust-)
"And since you are going to propose to people you are familiar with, then it could be more fun with more people, right!"
(...Well, forget it. It's Shera after all. The one who would complain more is Rem I guess. Gotta think of what to say to convince her. Maybe asking Shera to talk to her could help.)
"But... what do we need to do?"
"..."
"Diablo?"
"...kiss. We need to kiss."
"Oh, I see. But we already kissed before right? Do we need to do it again?"
"There was no such intention before so it seems it didn't count."
"Okay then. We can just do this again, right? I mean, we are married after all."
"...! Yeah..."
At this point, no more words were needed. Diablo silently moved his face towards hers. Shera too, closed her eyes, pouted her lips and waited for him. Each fraction of a second felt like an eternity, but it finally came.
Diablo felt his lips touching something soft. Something he has not touched for the first time. It was one of the pair of lips that kissed him as soon as came to this world.
It was not the same as last time though. This time, Diablo used a little of what he 'learned' from kissing Lamnites and Rafleisha and inserted his tongue on Shera's mouth by reflex. Shera was surprised for a moment, but immediately entrusted herself to him and followed his lead. She leaned on him, distorting the shape of her breasts on his chest.
"Hmm..."
"Nnn."
The room was silent, except for their kissing sounds. They kept this up for a few minutes, when they both separated to get some air.
"Puha! ...hah...hah."
They were both breathing heavily and, for an instant, Diablo had to face away from her. With her blushing cheeks, intoxicated eyes and heavy breaths, she was looking too 'ready for it'. Diablo would end up pushing her down if this kept going.
But, for now at last, he couldn't do it. He still had to worry about the other brides. After everything was solved, whatever he got all the brides he needed or not, then he would... try to respond to her expectations.
"...*cough* We-well, with this the ritual is completed."
"O-Oh! I see! I do feel something different. Like I'm connected to you in a way I can't describe, I guess I also feel stronger? You could have gone a little further though."
Diablo could hear some mumbling coming from her mouth, but decided to ignore it. He would listen to her complaints later. Now, it was Rem's turn.
That was chapter 1 but... somehow I wasn't sure how to rate this. I don't intend to put any r18 scenes but it still felt somewhat erotic to me. Maybe I will change it later. Sorry about any writing mistakes, english is not my native language.