One idea could be an OC who discovers their psychokinesis quirk gradually. They start with small things like moving a pencil, then as they train, they can lift heavier objects. This can lead to an interesting story arc of self - discovery.
The OC could start as a shy and withdrawn character, afraid of their psychokinesis quirk. But as the story progresses, they gain confidence. For instance, at first, they might accidentally break things with their quirk and be scared, but later they learn to control it and become more self - assured.
One way is through self - sacrifice. If the character uses their evil quirk to save a lot of people at great personal cost, it could be a step towards redemption. For example, if their quirk is something like mind - control and they use it to stop a powerful villain who is about to destroy a city, but in the process they lose their own ability to use the quirk. Another way is by showing remorse and actively trying to make up for their past actions. They could start doing volunteer work in the community, using whatever skills they have (even if related to their quirk in a non - evil way) to help others.
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.
To create a compelling OC with a sound quirk, start with the basics of the quirk. Decide on what exactly they can do with sound. Can they create sonic blasts? Or perhaps they can mimic any sound they've heard? Once you've nailed down the quirk, focus on the character's appearance. Maybe they have ears that are slightly larger to better pick up sounds. Their clothing could also be designed to enhance or control their quirk, like having sound - absorbing materials. In terms of personality, they might be confident because they know the power they hold, but also a bit lonely as not many people understand their quirk. And don't forget to give them goals. It could be something as simple as wanting to be accepted for who they are or as complex as using their quirk to change the world.
Communication is key. Have the male OC have deep conversations with each member of the harem. For example, he could talk about his dreams and fears, and the girls could do the same. This would create an emotional bond. Also, shared experiences like going on quests or fighting together can strengthen the relationships. For instance, if they face a powerful enemy together, they'll rely on each other and grow closer.
Often, there are original characters created specifically for the fanfiction. These OCs are the main focus with their dark quirks. There might also be some canon characters from the original work that the fanfiction is based on. They could be friends, foes or mentors to the OC. For example, if it's a fanfiction based on a superhero story, there could be a well - known hero who tries to help the OC control their dark quirk.
One good one piece male oc harem fanfiction is 'The Pirate's Harem'. It has an interesting male OC who has unique abilities and a great backstory. The harem aspect is well - developed, with each character in the harem having their own distinct personality and relationship with the OC.
One common theme is the growth of the male OC. As he travels through the Pokemon world, he not only gains more Pokemon but also matures in his relationships with the female characters in his harem. Another theme is friendship. Despite the harem aspect, the male OC often forms deep friendships with other trainers, both male and female. And of course, the theme of adventure is always there as he explores different regions in search of new Pokemon and experiences.
One popular Touhou male OC harem fanfic could be 'The Adventures of [Male OC Name] in Gensokyo'. In this type of fanfic, the male OC often has unique abilities that draw the attention of various Touhou characters. For example, he might be a powerful magician from another realm who accidentally stumbles into Gensokyo. Another one could be 'A Male's Journey through Touhou's World'. These fanfics usually explore the relationships between the male OC and the female characters in the Touhou universe. They often involve elements of friendship, adventure, and sometimes a bit of romance as the male OC gradually forms a 'harem' of sorts among the female characters.