When the concepts of jutsu from Naruto and Geass from Code Geass are combined. Like a Geass that can manipulate nature energy like Sage Mode in Naruto. This kind of crossover creates a whole new set of abilities and storylines that are super engaging and different from the original stories.
The combination of powers. In 'naruto code geass fanfiction', seeing how the Sharingan or other ninja abilities interact with the Geass power is really cool. For example, could a Geass user control a ninja under a genjutsu? It creates a whole new dynamic of power play.
A crossover might also involve the characters' moral compasses. The complex moral choices in Code Geass, like Lelouch's decision - making, could be juxtaposed with the good - vs - evil battles in Harry Potter. Harry, who is often seen as a paragon of good, could be influenced by Lelouch's more morally ambiguous actions, leading to some very interesting character development.
Lelouch would be really interesting. His complex personality and his ability to manipulate with Geass would make for some great interactions with Naruto. He could try to use Geass on Naruto, but Naruto's strong will might resist it, leading to a power struggle of sorts.
The concept of Naruto's tailed beasts being related to some of the powerful entities in WoW is quite fascinating. For example, some fanfictions suggest that the Nine - Tailed Fox could be related to an ancient and powerful demon in the WoW universe. This leads to some epic battles and storylines where Naruto has to either fight or team up with these WoW - related entities.
The crossovers where Naruto gets to use Samus' weapons are really interesting. For example, when he wields the Arm Cannon. It's a completely different kind of weapon compared to his kunai and shuriken, and it gives him a whole new combat style.
The crossovers where Naruto's chakra is compared to the magic in 'The Originals' are really interesting. It's like finding a parallel between two different power systems.
Perhaps a character from Game of Thrones could obtain the Geass power. Arya Stark, for instance. With her skills as an assassin already, the Geass power could make her an even more formidable force. She could use it to exact revenge on her enemies more effectively, or to infiltrate enemy strongholds with ease. This would change the dynamic of her character arc significantly.
One idea could be a crossover where Naruto characters end up in the Code Geass world and have to deal with the political intrigue there. For example, Naruto might try to use his talk - no - jutsu on the Britannian royalty.
Cultural clash is also a theme. Naruto comes from a ninja - based culture and Code Geass has its own complex society. When Naruto enters the Code Geass world in these fanfictions, there are often interesting interactions due to the differences in their cultures. And of course, the harem theme itself, with the relationships between Naruto and the various characters from both universes being explored, like love, loyalty, and jealousy among the harem members.
In Naruto fanfiction, Sasuke is often a very popular character. His complex backstory and his journey for power make him an interesting subject for fan - created stories. In Code Geass, Lelouch is extremely popular. His intelligence and his use of the Geass power to try and change the world are very appealing to fans.