Maybe Captain America. Captain America values honor and loyalty, and Rhodey with his military background would share those values. They could bond over their sense of duty. Rhodey might look up to Captain America as a symbol of leadership, and Captain America would respect Rhodey's skills and experience. So Captain America could be his closest ally in the story.
In the 'Avengers meet Rhodey' fanfiction, it could start with Rhodey being called in to help with a situation that the Avengers are already involved in. They might initially be a bit skeptical of each other, but as they work together, they start to respect and rely on one another. Rhodey could bring in his strategic thinking from his military background, which could give the Avengers a new perspective on how to approach their battles. There could also be a sub - plot where Rhodey has to prove himself to some of the more powerful Avengers members, like Thor or Hulk, and through his courage and skills, he earns their respect.
Well, it could be that Rhodey brings some new technology from the military side to the Avengers. He could introduce some advanced weaponry or strategic plans. And perhaps there will be some humorous moments as he tries to fit in with the more 'out - there' Avengers like Thor or Hulk. He might have a hard time understanding Thor's Asgardian ways at first but then they end up becoming good friends.
The friendship between Tony and Rhodey in the fanfiction is a complex and multi - faceted one. It's based on mutual respect, as they both recognize each other's skills and intelligence. Rhodey respects Tony's genius in engineering and Tony respects Rhodey's military acumen. They also have a deep emotional connection, which is often tested by the challenges they face, but always manages to endure, making their friendship a central and heartwarming aspect of the fanfiction.