sidekick
//ˈsaɪdˌkɪk//
Noun
sidekickSingular
sidekicksPlural
1
A close companion or assistant who accompanies and supports a more prominent person, especially a hero or main character.
The detective always solved cases with the help of his loyal sidekick.
2
A trusted friend or partner who helps someone in their activities or adventures.
Batman's sidekick Robin always helps him fight crime.