Serafall's face immediately fell. She looked as if she'd seen a monster. "Why is he here?!"
"Leviathan-sama, the Fallen Angel executive, Kokabiel, was defeated by Luo Guang. If it weren't for him, we would all be dead," Sona said, a lingering fear in her voice as she recalled the terrifying pressure from before.
"Huh? No way! He's the one who did it? I thought he could only use a Balance Breaker?" Serafall looked surprised. "I know Kokabiel. He's an arrogant one, but he's still an executive. His power is almost on par with the Old Demon Kings."
"What exactly happened? Tell your sister everything!" Serafall pleaded, clinging to Sona. But Sona didn't know how to explain it. She barely understood Luo Guang herself. Every time she thought she had reached his limit, he would do something to completely shatter her understanding.
"Why don't you know either? Aren't you two close?" Serafall asked, confused.
"Luo Guang and I are just classmates," Sona said with a weary sigh. That was Serafall's way; she was a bit overprotective. While Sona appreciated the family concern, it could be a hassle sometimes. Serafall was clearly imagining a much closer relationship than they had. Though, Sona did wish they were closer.
"What? What? So, are you saying you're the one pursuing him, Little Sona?"
"That's not it at all!" Sona's face tightened. Even as sisters, she couldn't understand how Serafall's mind worked.
"Waaaaah... Little Sona is all grown up! She's going to leave me!" Serafall wailed, hugging Sona again. The sight of the Demon King's breakdown drew stares from everyone around, making Sona want to disappear. It was especially embarrassing when Luo Guang looked over.
After a long while, Serafall finally calmed down and walked over to Luo Guang. Luo Guang thought she was going to challenge him, but before he could react, Serafall took his hand.
"I have to thank you. If you hadn't defeated Kokabiel, I might never have seen my Little Sona again." Serafall said, patting her chest. "Whatever reward you want, I'll do my best to grant it!"
"How about your 'Little Sona'?" Luo Guang said casually.
Everyone froze, thinking they'd misheard. Sona's face turned beet-red in an instant.
"Just kidding," Luo Guang chuckled. "So, any reward is fine?"
"Uh... as long as it's not Little Sona," Serafall said meekly. Seeing her like this, Luo Guang was tempted to tease her again, but he decided against it.
"To what extent can you reward me?"
"The maximum within my authority. As long as what you want isn't harmful to the Underworld, I can grant it," Serafall said seriously. "After all, you've done a great service for us. If you were a Low-Class Devil, you could demand to be promoted to a High-Class Devil without a problem. If Kokabiel's plan had succeeded, I would've been so grief-stricken that I would have led my army to attack the Grigori headquarters, and the Great War would have started again."
"So, you can say your contribution was stopping a war."
This was true. Luo Guang thought for a moment and said, "One is your personal ice magic grimoire. As for the other, I'll take the single greatest power you can grant me within your authority as a Demon King."
"So you want me to agree to do one thing for you?" Serafall considered. "Okay, as long as it's not harmful to the Underworld and doesn't involve killing innocents, I can agree to that."
"But are you sure you want to learn my ice magic? I heard from Little Sona that you even learned holy light. If you try to learn too many things, you'll get overwhelmed." Serafall offered a sincere warning.
"It doesn't matter. For the sake of common sense, there's nothing in this world I can't learn," Luo Guang said calmly.
"Well, if you're so confident, I'll have Little Sona give it to you later." Seeing that her advice was useless, Serafall didn't press the issue. Everyone has their own path. Besides, Luo Guang's talent was truly exceptional.
"Sigh, with what Kokabiel did, there's going to be a lot of trouble," Serafall muttered to herself. Luo Guang didn't respond; these weren't his problems to solve. He looked at the girls. "It's getting late. I'm heading back."
With that, the girls said their goodbyes to Luo Guang.
"We owe him again," Rias said with a sigh.
"The more you owe, the less you worry. Besides, Rias, you're already his fiancée, so there's no such thing as owing him. But as for me... I might have to sell myself just to repay him," Akeno Himejima said, covering her mouth with her hands, her eyes twinkling.
"Akeno, you... never mind. Just go and settle the two from the Church," Rias said, knowing what Akeno was thinking but not knowing what to say, so she changed the subject.