Iron Man admits that in fact the rest of the Avengers are more afraid of one of their fellow heroes than the rest and its not the Hulk.
Iron Man is more afraid of the avenger than the Hulk. While the Hulk is a truly terrifying member of the Avengers due to his unparalleled strength and utter unpredictability there is another great hero from Earth that Iron Man finds even more terrifying.
The Avengers roster has had no shortage of horribly strong members since the team was first introduced in Avengers #1 by Stan Lee and Jack Kirby. The original group alone had a number of fearsome creatures including the Hulk Thor and AntMan. While AntMan may seem out of place in terms of being a fearinducing one like a literal god or a gigantic angry monster.
Hank Pyms mind is something to be afraid of as he was the one who created Ultron and constantly comes up with other fanciful ideas however as tools It can get on its knees if it falls into the wrong hands. Since then the Avengers have recruited increasingly terrifying heroes to join them such as a daywalking vampire with Blade an immortal and emotionally unstable killing machine with Wolverine and a true demon with Ghost Rider. However according to Iron Man none of them hold a candle for fearsome Captain Marvel.
In Captain Marvel #1 written by Kelly Thompson and Carmen Carnero Carol Danvers makes her return to the superhero scene by battling a type of sea monster that resembles the Kraken. After she defeats the monster Iron Man approaches her and asks to talk to her about her plans to move forward now that shes back on Earth and plans to remain a hero on Earth at least for the time being. During their meeting Tony asked Carroll about joining the Avengers and Danvers responded by asking Stark why she talked to him about being reaccepted in the Avengers because hes not even the captain. Tony replies I was nominated to talk to you about it…because well youre scary.
Iron Man is more afraid of the avenger than the Hulk. In this issue Iron Man confesses his feelings for Captain Marvel because he found her the teams most feared Avengers but his confession also points to something else totally awesome. Tony is nominated by the Avengers with the lineup at the time including Thor Captain America Ghost Rider and Blade and decides hes going to talk to Carol because shes scary. This means that Iron Man isnt the only one who thinks Captain Marvel is the scariest Avenger but every Avenger thinks shes the scariest even those who literally battle demonic creatures and space monsters on a regular basis.
There is no specific reason why the Avengers are afraid of Captain Marvel although she is thrilled that they do. Captain Marvel is a very powerful being in the Marvel Universe not ruling anything out but Carol Danvers as a person is a fun sense of humor with interconnected issues and a desire to be the best person she can while also spending time having fun with her friends. However while fans know Carols personal side well other Avengers basically see her as the leader among them who uses her power to destroy any threat they face. Seeing these powers in action should elicit fear as they are a force on a cosmic scale rather than the super strength shown by the Hulk who is powerful but not even in the same league as Captain Marvel.
Plus in terms of Iron Man specifically Carol Danvers doesnt particularly like Tony Stark after Iron Man and Captain Marvels Civil War II conflict and she casually threatens to throw him out of skyscraper windows fairly regularly since she certainly It has the power to support those threats and a healthy fear of them is clever on Tonys part. Iron Man asserts that the Hulk is not the most terrifying member of the Avengers because according to the Avengers that honor goes to Captain Marvel.