Mushoku Tensei with gacha system

few minutes before the duel took place

Eris barely looked at him, her expression one of disinterest. "Hmm? Another one of Father's new recruits?" she muttered, her tone laden with disdain.

I took a deep breath and approached her. "Hello, Eris. My name is Rudeus Greyrat. I've been hired to be your new teacher."

Eris's eyes flicked up from her food, narrowing as she took in my appearance. "A teacher? What makes you think I need one?"

I tried to keep my voice calm and professional. "I understand that you might be skeptical, but I assure you that I'm highly skilled. My age doesn't reflect my abilities. I've been trained extensively in lots of arts and have a lot to offer."

Eris snorted, rolling her eyes. "Ha! You think you can teach me? I'm already better than most adults at swordsmanship. Why should I listen to a boy who looks younger than me?"

I felt a surge of frustration but forced myself to stay composed. "It's not about my age or appearance. It's about what I can teach you and help you achieve.there are many skills that are required by a human besides sword skill. If you'd give me a chance—"

Eris interrupted me with a sharp tone. "Give you a chance? Why should I? I only need Ghislaine. She's the only one who's ever been able to keep up with me."

Her words were a blow to my pride. I was here to prove myself, but she was making it almost impossible. "I understand that Ghislaine has been a great teacher, but that doesn't mean you should dismiss what I have to offer outright. If you want to see if I'm truly capable, perhaps we should settle this with a duel."

Eris's eyes widened in surprise, her attitude shifting from disinterest to fiery defiance. "A duel? Are you serious? Fine, if you want to prove yourself, then let's do it. I'll show you that you're no match for me!"

I nodded, accepting the challenge. "Alright. Let's have a duel. We'll see if I'm worthy of your respect and if my win I become your teacher"

Philip, who had been observing quietly, finally spoke up. "Very well. I'll arrange for a suitable place for the duel. It's important that you both understand each other's capabilities."

Eris stood up abruptly, her face flushed with excitement. "Come on, then! Let's get this over with!"

As we left the dining hall, I could feel the weight of the upcoming duel hanging over me. This was not just about proving my skills; it was about gaining Eris's respect and establishing my role as her teacher.

The sun was beginning to set as we arrived at the garden, where a suitable area had been cleared for the duel. The garden, with its neatly trimmed hedges and well-maintained grass, was now a makeshift arena. I took a moment to prepare, deciding to use only Gwen's magical constructs in the duel. Through Rudeus's memories I know that this world has barrier magic which is a little similar to magical constructs but Gwen's abilities are way superior and versatile and I believe I could pass this as a new spell invented by me which would increase my credibility even further

Eris stood at the other end of the cleared area, her stance firm and confident. She had changed into her training clothes, her wooden sword held tightly in her hand. She was ready, and her eyes gleamed with anticipation.

Philip stood nearby, his expression a mix of concern and curiosity. "Remember, this duel is not just to prove who is better but to see how well you can work together. Make sure it's fair and respectful."

I nodded, acknowledging his words. "Understood."