Riku has done a lot of growing up for someone his age, having a father that left him, his siblings, as well as his mother shortly after his youngest sister had been born. He was angry at his father for abandoning them as if they were nothing. It has made him pessimistic about the world, at least for a time. When his mother remarried, Riku became a little more optimistic, not wanting to spoil his mom and younger sibling’s newfound happiness. Despite this, however, Riku was still hurt by what his father had done. The way Riku sees it, his father doesn’t deserve his forgiveness for abandoning them, and he wouldn’t be afraid to say it to his father’s face if they were to somehow ever meet again.

Whenever a subject is brought up that Riku doesn’t particularly like, he either acts in one of two ways, nonchalant or annoyed, occasionally throwing in a hint of sarcasm with one-word replies. Riku also tends to be straightforward. This sometimes makes him look like a jerk most of the time, however, he isn’t like that all the time. The reason why he does come off this way (especially towards people he’s never met before), is because he uses it as a defense mechanism because he doesn’t want to be betrayed in the same way his father betrayed his own family. In his mind, it’s better to build up these kinds of ‘walls’ so that way he doesn’t feel the same kind of disappointment he feels for his father (as well as hatred). This is ultimately why it’s hard for Riku to make friends, or at least, that is what he thinks.

When he’s trying to become someone’s friend he honestly doesn’t know what to say. Rather than words, he portrays his appreciation towards someone he is friends with through his actions; not his words.

Riku was the first child out of four in his family. His father, Touma Masamune, was a Pro-Duelist while his mother, Kira, worked at home while also taking care of him, his younger brothers, and his sister. Riku had admired his dad, and by the age of seven, he had started learning how to play duel monsters with his dad, and even sometimes his mother whenever his father wasn’t around. Eventually, dueling had become a family thing once his younger siblings got a bit older. It became like a family game night for them every weekend. There would always be someone within the family who had won, however, Riku knew very well that his father, and possibly even his mother wasn’t giving it their all.

The talks between Riku and his friends at school were mostly also about duel monsters as well as his dad’s most recent wins. Riku enjoyed his life as he was growing up. But then, one day as he and his family were waiting for him to get home for their game night, he had never come home from work. Riku’s mother had tried desperately to learn what had happened, however, oddly enough, no one knew what had happened to Touma. Riku was also worried, wondering if something bad had happened to his father. Years passed and eventually, Riku came to one simple conclusion. His father had abandoned them. After he made that realization for himself, he grew angry whenever his father was mentioned. The man that Riku admired the most crushed his heart, and because of that, the love he had for his father grew into hatred.

Riku had even stopped playing Duel Monsters for a short time because of it. Instead, he’d go ride his skateboard for hours on end until he got either tired or bored. His mother had become worried for her older son, noticing how his father leaving them had greatly affected him. What’s more is that his grades had started to fall slightly in school, as well as getting into a few fights here and there with other students. It became a ‘normal’ thing for Riku by the time he got into junior high. After a time, even more, time passed, and Riku and his family eventually moved to Silvershine. The first thing that Riku and the others had noticed right away was that Dueling was more on the rage here than back at home.

Riku’s siblings had attempted to try and Riku back to Dueling but to no avail. That was when his mother finally decided to have a sit down with him. Kira had even managed to get Riku to duel her, which was nice. However, she knew that he wasn’t all that interested, given the fact that he’d draw and simply pass his turn without care. His mother sighed and started to speak. “Okay, listen Riku. I know that your dad leaving us hurt you … us …” She paused, feeling the hurt herself that she had bottled up inside as she spoke to her oldest son. “But, that doesn’t the love you have for this game is his. Sure, he introduced it to you, but that doesn’t change anything. I know that you still love the game deep down, and that’s okay. What I’m trying to say is … Don’t let what your father did stop you from dueling, okay?” She said softly, as she reached out, placing a hand on Riku’s. As he looked up, he saw his mom smile for the first time in a long while. Riku gave his mom a gentle smirk and replied, “Alright, mom.” From then on, he wasn’t gonna let what his father had done question his love for the game. He also vowed that he wouldn’t be like his father either as a duelist. He would carve out his path and shape it the way he wanted it to be.

The duel between Riku and his mother continued, and with a newly found spark within him, Riku dueled with his all as did his mother, however, the victory went to Riku. Shortly after he had won the duel, Riku even found himself smiling. He thanked his mom for talking with him. “Ya know, there’s a Duel Academy named Liberta here that you could more than likely attend. If you want to pass their entrance exam though, your gonna have to prepare. I hear it's pretty tough,” Kira said, glancing between Riku and the starlit sky while sitting next to him on the backyard porch. “Yeah, but my grade’s from last year aren’t as good, they may request a record of my transcript from my former school,” Riku pointed out. They weren’t necessarily terrible but, Riku knew that he could have at least done better.

“Since when did you let that stop you, though?” Riku’s mother giggled as the question gently rolled off her tongue. Riku chuckled and said, “Ya got me there. Well, I’ll give it a shot!” Riku had said, determined to pass the entrance exam to become a student at Liberta. He had plenty of time to practice, preparing himself for the entrance exam as best as he could. He had thought long and hard of ways of remaking the deck that his father had given him. Riku looked over the cards carefully, deciding on what cards to keep and what cards to get rid of. If he had it his way, he’d pitch the deck in a lake and just make a new one. However, since they had just recently moved to Silvershine, Riku’s mom still needed to look for work. The money that was poured into their new home was from their father’s account, but since he disappeared with no trace of him left behind, Kira has been deemed the owner of the account.

After a month of practice and reconstructing his deck, it was finally time for Riku to take the entrance exam. The first portion of the exam was a written exam, which … was pretty boring to Riku. He never liked taking actual tests in this regard. He also was never all that great at written exams either. However, that didn’t deter him not wanting to at least try his best. After the written exam, came the fun part - the practicals. It was one-to-three duels against him with proctors working for the academy. Despite his score from the written exam, which was not the greatest, he passed the practical with flying colors. Even though he did well on the practical, he bombed the written exam, which had landed him within the B-Rank margin of first year students and was placed in the House of Legacy dorm.