Ant-Man 3: 10 Things You Need To Know About Kang The Conqueror
2. He Was A Hero
When Kang was a teenager, a bully slit his throat, forcing him to recover in hospital for a year. To right this wrong, Kang went back and stopped this incident from happening. He then explained to the Nathaniel Richards of that time that he shouldn't doubt himself since he will inevitably conquer space-time.
Nathaniel was terrified of the idea of becoming a chronal dictator and used Kang's tech to escape. Nathaniel transported himself to the 21st century around the same time the Avengers had disbanded. When a group of teenage superheroes decided to form their own team called the Young Avengers, Nathaniel joined them. He took the alias Iron Lad and swore to uphold justice, hoping this would prevent him turning into a supervillain in the future.
Because Kang would cease to exist if Iron Lad maintained his superhero persona, he ventured to the 21st century to bring his younger self back to his original timeline.
It's worth mentioning that Scott Lang's daughter, Cassie, is a member of the Young Avengers and worked alongside Iron Lad. It's heavily rumoured that the Young Avengers will have a part to play in the third Ant-Man, so might it be possible that this storyline comes into play?