Idea for a champion (ADC)

Okay, so I was thinking a champion with a pet dynamic, the champion uses a double-barrel long rage file that reloads similar to a stacked double-barrel shotgun. Yes, a reloading mechanic champion. The pet is connected to the champion by a tether, and the pet will run at only enemy champions that the ADC as targeted. How that works, is the champions autos put some sort of mark onto the champion. The ult then switches the abilities to have more control over the pet and empowers the champion's auto-attacks, or switches the gun to a single-shot rifle that increases range and double auto damage. It's kind of like having a ranged marksman and a bruiser in the same kit, kind of like Gnar, but not exactly. Lore wise, I was thinking that it would be a female champion from the Shadow Isles.