Inoue Orihime from Bleach itself could be a part of the harem. Since she already has feelings for Ichigo in the original series, it would be a natural fit. Also, Saber from Fate/Stay Night. Her noble and powerful nature would contrast well with Ichigo's more rough - around - the - edges style. Another could be Rem from Re:Zero. Her loyalty and love - stricken nature could add an interesting dynamic to the harem as she falls for Ichigo.
Rukia could be one of the characters. Since she has a deep connection with Ichigo already in the original series, it would be easy to develop a more romantic aspect in the harem setting. Orihime is also a likely candidate, as she has strong feelings for Ichigo. And from other animes, a character like Saber from 'Fate/stay night' could be interesting. Her noble and powerful nature would contrast with Ichigo's more rough - around - the - edges personality.
In a crossover with Naruto, Sakura could be a potential member. She's strong - willed and might be attracted to Ichigo's power. From Fairy Tail, Erza could also be part of the harem. Her no - nonsense attitude and strength would make for an interesting dynamic with Ichigo. And from One Piece, Nami could be in the harem. Her intelligence and love for treasure might draw her to Ichigo.
Maybe Naruto from Naruto could be a crossover character. His ninja skills and Ichigo's combat abilities could create some unique fight scenes. Also, their different ideologies about friendship and power could lead to some great character interactions.
Rukia could be one of the characters in the harem. She has a long - standing relationship with Ichigo and her own strong spiritual powers. Orihime could also be part of it. Her kind - hearted nature and unique abilities would add depth to the harem dynamic. Another potential character could be Neliel. As an arrancar herself, she could have an interesting relationship with arrancar Ichigo.
In this fanfiction, characters like Luffy from One Piece might be involved. Luffy's carefree yet determined nature would contrast with Ichigo's new god - like presence. Also, characters from the Bleach universe itself could have new relationships with Ichigo. For instance, Aizen might see Ichigo's godhood as a threat or an opportunity, leading to a complex plot development.
Well, obviously Lucy from Fairy Tail would be a likely candidate. She already has a strong connection with Natsu in the original series. Then from the world of Bleach, Rukia could be an interesting addition. Her cool and collected nature would contrast with Natsu's hot - headedness, and her Soul Reaper powers would add an interesting dynamic to the harem. Also, from Attack on Titan, Mikasa could be in the harem. Her strong combat skills and protective nature towards Eren could translate into a similar protectiveness towards Natsu in the fanfiction.
Gwen could be one of the characters in the harem. She already has a close relationship with Ben in the original series. Another could be Kai Green. She's shown interest in Ben before and could easily be part of a harem in a fanfiction. Also, female aliens like Rook's sister (if she exists in the fanfic's version) could be part of it.
In a crossover with Sailor Moon, Sailor Venus could be part of the harem. She is a strong fighter like Goku in her own way, and their different powers and personalities could create interesting dynamics.
Hermione Granger would definitely be a key character. Her intelligence and magical ability would make her an important part of any harem situation around Harry. Then there could be characters like Arwen from 'Lord of the Rings'. Her beauty and elven magic would bring a different dynamic. Also, Sakura from 'Naruto' could be included. Her medical ninjutsu and strong will could add to the mix in the harem.
Obviously, Annabeth Chase could be one of the main characters in the harem. She already has a strong connection with Percy. Then, there could be Thalia Grace, with her cool and powerful demigod nature. From other mythologies, Artemis could be an interesting addition. Despite her vow of chastity, in a fanfiction world, she could be drawn to Percy in a different way. Also, maybe a character like Katara from Avatar: The Last Airbender could be brought in through some sort of crossover magic, adding an element of water - bending to the mix.