The Soul Reapers could be involved too. Some of them might notice that Ichigo is acting strange and try to figure out what's going on. Captains like Byakuya or Kenpachi could potentially cross paths with Ichigo during this time. And then there are the Hollows. They might sense that something is different about Ichigo but not be able to fully understand why he seems weaker than before, which could lead to some interesting confrontations.
Perhaps in the fanfiction, Ichigo hides his powers because he wants to live a normal life for a while. He could be tired of all the battles and responsibilities that come with his power. So, he tries to blend in at school and with his family, but of course, it's not easy as his true nature keeps showing up in small ways.
Bob the Shinigami might be able to use Naruto's shadow clone technique. He could create multiple clones of himself to perform different tasks like scouting or distracting enemies. In return, Naruto could gain the ability to sense souls like Bob does, which would give him an edge in battles, especially against opponents who use genjutsu that affects the mind and soul.
Ichigo might gain the ability to manipulate shadows with the Darkness Zanpakuto. He could use the shadows to hide, to attack from unexpected angles, or even to create illusions. This would give him a whole new set of tactical options in battles. He could also absorb the darkness around him to strengthen his attacks or heal himself, much like how he currently absorbs spiritual energy.
Naruto's chakra - based powers and the fem shinigami's reiatsu - based powers could create some unique combinations. For example, Naruto could use his shadow clones to help the fem shinigami in battle while she uses her zanpakuto to enhance the strength of the clones.
The plot could involve Ichigo discovering he has gamer powers. Maybe he can level up his combat skills like in a game, which gives him an edge in battles against Hollows. He might also gain access to in - game items that have real - world applications in his fight to protect the Soul Society.
A powerful Hollow that has the ability to disrupt Ichigo's gamer powers could be the main antagonist. This Hollow might be able to hack into Ichigo's power system, so to speak, and cause glitches in his abilities, making it difficult for him to fight.
I hope there isn't such fanfiction. Such content involves non - consensual and inappropriate themes which go against the values of a healthy fictional creation.
Maybe their powers could combine through a magical artifact. Say they find an ancient talisman that links their powers. When they touch it together, their powers merge, allowing Ichigo to use his Bankai with a Quincy - like energy enhancement, and Candice to have access to some of Ichigo's Hollow - based speed and agility. This could open up a whole new range of combat abilities for both of them.