Natasha Romanoff is an interesting character in this regard. In the Age of Altron, she has her own skills and insights. When it comes to Tony's 'whump' situations, she could be using her espionage skills to figure out what's wrong with Tony or how to help him. Additionally, Bruce Banner is also fascinating. His struggle with the Hulk inside him can parallel Tony's own internal and external struggles in the fanfiction. Their interactions during Tony's difficult times can create some really engaging storylines.
Vision could be one. His unique nature in the Age of Altron setting can add a lot to the fanfiction. He might interact with Tony in different ways during Tony's 'whump' moments, either trying to help or having a different perspective. Another could be Wanda. Her powers and her own emotional journey can intersect with Tony's story in interesting ways.
One common theme is the struggle and pain Tony endures. It could be physical pain from battles or emotional distress due to various situations in the Age of Altron setting. Another theme might be his isolation as he faces difficulties alone, with the events in the fanfiction highlighting his journey through tough times.
There could be a best friend character. This person might be heartbroken when Tony leaves. They might have shared a lot of secrets and experiences together, and Tony's departure would leave a big void in their life.
Well, they could have a wise old mentor figure. This person could be an older neighbor who has lived through a lot and gives them valuable advice when they face difficulties in their relationship or in their adventures.
Pepper Potts could be an interesting addition. She could be in on Tony's undercover plan and be his contact on the outside. She could also provide some comical moments when she has to cover for Tony or when she tries to communicate with him secretly while he's undercover.
There could be the foster parents. Maybe they are a kind - hearted couple who try their best to understand Tony despite his quirks. Another character could be a foster sibling who is initially jealous of Tony's intelligence but later becomes his friend.
Natasha Romanoff would be an interesting character to include. She's very perceptive and could be the one to first notice the change in Loki's behavior towards Tony. And then there's Bruce Banner. His scientific mind could interact with both Loki's magic and Tony's technology, and he could also offer some unique perspectives on their relationship, perhaps warning Tony about the risks of getting involved with Loki.
Gibbs would be a great character to include. He could be the one who notices the growing relationship between Ziva and Tony before they even realize it themselves. He might give them some sage advice or just be there as a sort of father figure guiding them through the early stages of their relationship.
Perhaps there is a neighbor. The neighbor could be an older person who has seen similar situations in the past. They might notice the signs of trouble in Tony's family and try to offer some form of support or advice. Also, there could be a school counselor. Tony might turn to the counselor at school after the beating, and the counselor could be a key figure in getting Tony the professional help he needs and dealing with the situation.
I really like 'In the Shadows'. In this fanfiction, Tony endures a lot of physical and emotional pain. The author does an amazing job of portraying his vulnerability. It also has some great character interactions that add to the overall story. It's a must - read for fans of Tony Whump in NCIS.
Betrayal is another theme. Sometimes, Tony is betrayed by someone he trusts, which adds to his whump. This could be a fellow agent or someone outside the team. It makes his situation more difficult and the story more dramatic.