First, give your OC a distinct personality. They could be shy and reserved but with a hidden strength, or super confident and a bit of a troublemaker. Next, design a unique quirk. It could be something related to nature, like controlling plants, or a more mental-based quirk like mind - reading. For appearance, think about what would make them stand out in the My Hero Academia world. Maybe they have colorful hair or a really cool costume. Also, consider their backstory. A tragic past can add depth, like if their family was killed by villains and they are determined to become a hero to avenge them.
One common plot device is the OC having a unique quirk that draws the attention of the harem members. For example, if the OC has a healing quirk, it could make them valuable in a world full of heroes and villains. Another is the introduction of a common enemy. This forces the OC and the harem to work together and strengthens their relationships. Also, the OC's backstory often plays a big role. Maybe they come from a poor background and their determination to succeed in the hero world despite that attracts the harem members.
The male OC could be designed with a laid - back personality but with a hidden intensity when it comes to using his quirk. Physically, he could have longish hair that he often brushes out of his face in a cool way. He might wear a combination of modern streetwear and some traditional hero - like accessories, like a cape - like scarf. His quirk could be related to energy projection, which gives him an edgy look when he uses it, with glowing energy coming from his hands.
Well, he could be an OC with a healing quirk. In the fanfiction, he starts helping out injured students during training sessions. This catches the attention of several female characters. Some might see him as a valuable asset to their future hero teams, while others develop a more personal attraction. The harem could then be formed as these girls start competing for his attention in a friendly way, like trying to bring him the best lunches or inviting him to exclusive study sessions.
Perhaps the OC has a hidden past related to a villain organization, and the harem members are initially suspicious but as they get to know the OC better, they realize there's more to the story. This could create a lot of drama and conflict as the OC tries to prove their loyalty while also dealing with their growing feelings for the harem members.
An interesting concept would be an OC who has a quirk that is based on art. For example, they can bring paintings to life. This OC could be a part of an art school within the My Hero Academia universe and use their quirk to fight villains who are attacking art galleries or museums. They would also have to train their quirk to be more combat - effective.
In such a fanfiction, from Naruto, Sakura could be in the harem. She's strong - willed and has her own set of skills. From My Hero Academia, Ochaco Uraraka could be there. She's kind - hearted and has an interesting quirk. And of course, Hinata from Naruto is also a likely candidate with her shy yet determined personality.
A good way to create an interesting My Hero Academia OC for your fanfic is to look at the existing characters for inspiration. Notice how the heroes and villains in the series have different quirks and personalities. Your OC could have a quirk that is a combination of two existing ones, but with a new twist. For instance, if you combine the elasticity of Deku's quirk in some of his forms with the fire - based aspect of Todoroki's quirk. In terms of personality, they could be an introvert who is forced to step out of their comfort zone because of their quirk. Their journey in the fanfic could be about learning to accept themselves and their powers.
In 'My Hero Academia OC Abuse Fanfic', a frequent theme is the psychological impact on the OC. The abuse can cause the OC to develop various psychological issues such as trust issues, low self - esteem, and fear. It also might explore the theme of revenge. The OC, after suffering abuse, could seek revenge against those who wronged them. Additionally, there could be a theme of friendship emerging as the OC might find a few true friends who help them overcome the abuse and regain their confidence.
One possible plot could be an OC who is a gamer and discovers they can use their gaming skills in the My Hero Academia world. For example, they might be really good at strategic planning in games, and this helps them create unique battle strategies against villains. They could start as an underdog, with classmates doubting their abilities because they seem more focused on gaming than hero training. But as they prove themselves in battles, they gain respect and also inspire others to think outside the box when it comes to heroics.