In DxD Starting with Sign-Ing in as the Red Dragon

Before Akira could finish his internal monologue, he heard the familiar chime of the system notification.

[Ding!~]

[Congratulations, host! You have triggered a Villain Sign-In Event!]

[Sign-In Level: Rainbow.]

[Sign-In Type: Event Sign-In.]

[Sign-In Event: Offer a New Demon King to the Demon Clan.]

[Event Requirements: Marry the current Demon King's sister, Rias Gremory, and make Grayfia your subordinate.]

Demons are a race that values strength above all else. The current Demon King rose to power by defeating the previous Demon King, and to solidify his legitimacy and power, he married into the bloodline of the former Demon King.

So, if the former Demon King's lineage wishes to rise again, what should they do?

That's right—they should marry into the current Demon King's bloodline to claim legitimacy.

Just as the Ming Dynasty succeeded the Yuan Dynasty, and the Qing Dynasty succeeded the Ming Dynasty, even though they overthrew their predecessors, they still chose to inherit their claims to maintain legitimacy.

[Objective: Seduce or conquer Rias Gremory (Gold), seduce or conquer Grayfia (Rainbow), marry both, and claim the title of the new Demon King (Rainbow).]

After reading the system notification, Akira's expression turned微妙.

"Just a moment ago, Sirzechs said... that I could ask him for anything if I needed help."

"Well, now I have a need—no, I've created a need out of thin air."

"How am I supposed to tell him: 'I don't want anything else, just your sister and your wife?'"

A few seconds later, Akira calmed himself and spoke slowly.

"Grayfia, there's actually something I'd like to ask of Sirzechs-sama."

"What is it, Akira-sama? You can speak freely."

"I'd like to ask for his permission—to allow me to form a marriage contract with his sister, Rias Gremory."

"I... wish to become Rias's fiancé."

Akira had already agreed to a fake marriage with Rias.

Now, with the added task of becoming the Demon King, this marriage had become even more necessary.

Grayfia, the Queen of the Underworld, lived up to her title. Even such a shocking marriage proposal didn't faze her. She simply glanced deeply at Rias.

With her political acumen and understanding of Rias, she immediately realized that Rias must have had a hand in this.

"Akira-sama, is this Rias's idea, or your own?" Grayfia cut straight to the point.

Akira's response was calm.

"It's Rias's idea, as well as my own."

"Akira-sama, you must understand that neither the upper echelons of the Underworld nor the Phenex family will simply abandon their existing marriage contract just because you and Rias have feelings for each other," Grayfia warned.

"Of course, I understand that," Akira nodded.

"No! I don't understand this at all! Grayfia, I think this is something we can discuss!" Rias stepped forward.

"Sona said she doesn't want to marry Akira."

"If she doesn't want to marry him, then I will!"

"If she doesn't want him as her fiancé, then I'll take him!"

"I know the upper echelons have different expectations for us young demons."

"Sona's duty is to unite with the former Demon King's bloodline, while mine is to produce pure-blooded demon offspring."

"Since both Sona and I are dissatisfied with our current arrangements, why not swap?"

"I'll unite with the former Demon King's bloodline, and Sona can focus on producing pure-blooded demon offspring!"

"Sona wants someone with both strength and intellect, and she can only find that among pure-blooded demons."

"As for me, I really like... no, I love Akira. I don't care about pure blood or not."

"So, the best solution is—to swap our marriage contracts!"

Rias's explanation left Grayfia silent.

If Sona was willing... this might actually work.

"Akira-sama, if I'm not mistaken, this was your idea, wasn't it?" Grayfia turned to Akira.

"Grayfia, does it matter whose idea it was? What matters is whether it's feasible, right?" Akira shrugged.

"Besides, when did I say I was going to use this method?"

"Huh?"

Rias turned to him, her eyes wide with disbelief.

Akira, how could you back out now?

"Rias, don't be so impatient."

See? She's always in a rush.

"I only said I don't want to swap marriage contracts, not that I don't want to marry you."

"So... Akira-sama, you mean..." Grayfia narrowed her eyes.

"I mean, we should follow the ancient customs of the demon race—let strength decide."

"Akira-sama, by saying this, you're implying that you're prepared to fight the Phenex family. Am I correct?" Grayfia pressed.

"You are absolutely correct. There's no issue with that."

"Very well. In that case, before you face the Phenex family, why not warm up with this little test?"

Grayfia activated a teleportation circle, inviting Akira to step inside.

As she watched the handsome young man step into the circle, Grayfia's thoughts swirled with emotions.

Akira had spent more time with her than even Sirzechs had.

If it weren't for Akira helping her train, she might have died during the demon civil war.

Without Akira, she would never have reached her current level of strength.

In her heart, Akira held a special place.

However, when Akira took human form, he didn't inherit her or Sirzechs's bloodline.

If Akira had inherited her or Sirzechs's blood, even if he were a failure, she would never have given up on him.

But alas, he was tainted with the blood of Leviathan, and Sirzechs had become... what he was now. No matter how talented Akira was, he was destined to be discarded.

Living a peaceful life wouldn't be so bad.

That's what Grayfia had originally thought.

But now, things had taken another unexpected turn. Akira had defeated Sona!

Even though he had used a demon beast, a victory was still a victory.

Grayfia pondered for a long time.

In the end, she couldn't help but feel a twinge of compassion.

[If he's regained his strength, it means the heavens haven't abandoned him yet.]

[If that's the case, then I should give him a chance. This is my way of repaying him, even if it's just a small gesture...]

Grayfia's decision was... not to report this.