sidekick

This term carries a strong connotation of loyalty and unwavering support, often evoking the image of a duo where one person is clearly the lead and the other is the helper. It is frequently used in the context of fiction, particularly in detective novels or superhero comics, where the assistant serves as a foil to the protagonist's personality. While it can be used in real-life casual conversation to describe a best friend or a constant companion, it implies a hierarchical relationship. The sidekick is not an equal partner but a supportive figure who handles the smaller details or provides emotional stability for the leader.