One of the most memorable boss fight stories for me was against Ornstein and Smough. It was a battle of endurance and strategy. I first focused on Ornstein as his attacks were more predictable. But when I got him down to low health, Smough absorbed him, becoming Super Smough. His attacks became more powerful and had a wider range. I had to constantly dodge and look for openings. Eventually, I managed to defeat him after many attempts, and it was a huge sense of accomplishment.
Yes, there might be. The world of fanfiction is vast and diverse. With the popularity of both Harry Potter and the concept of Ryuji Jakkan (assuming it's a known or created concept), it's very likely that some fans have combined them in their creative works. However, it may not be as mainstream as some other Harry Potter fanfictions.
My favorite has to be the Artorias of the Abyss fight. Artorias was a tragic figure. His moves were so fluid and his attacks were strong. He seemed like a force of nature. I remember his leaping attacks and how I had to time my dodges perfectly. The atmosphere of the fight, with the dark abyss all around, added to the tension. I felt like I was in a real duel with a great warrior. I had to be patient and wait for my chances to strike back. After a long battle, I emerged victorious, and it was a fight that I'll always remember.
One common theme could be power and its consequences. Since Percy is an elder god, he has a great deal of power, and the fanfiction might explore how he uses or misuses it.
A common theme is friendship - turned - love. They start as friends and gradually develop deeper romantic feelings. Another theme is mutual support. They help each other through tough times, like Haru being there for Ryuji when he has family issues or Ryuji giving Haru confidence in social situations.
One common theme is friendship. Since Ryuji is part of the B Project, fanfics often focus on his friendships with the other members. Another theme could be his journey to achieve his dreams as an idol.
One common theme could be redemption. Given Kamoshida's actions in the game, fanfic might explore his path to redemption in relation to Ryuji. Another theme could be friendship or an unlikely bond forming between them.
I recommend I Am the Legendary Boss. The plot of this novel is that the protagonist reincarnates into the game as GM01 and conquers the entire game world in the process of fighting the BOSS. The novel mainly told the story of how the protagonist used the advantages of the game's skills and equipment to become the strongest BOSS in the game and fight with the players. I hope you like this fairy's recommendation. Muah ~😗