League of Legends has evolved over time and Riot Games' way of working has become more refined. The developer has streamlined the way it creates new content for the game and has much better technology than in the early years. This means that we no longer hear about canceled champions or ideas that cannot be implemented. Of course, there are a few exceptions with abilities removed like Vex, but in most cases anything that doesn't make it into the game is because the devs don't view it as a positive and not because 'it cannot be implemented.
A champion who will never arrive in League of Legends
The situation was very different in the past, and we heard about all kinds of canceled champions or ideas that couldn't be implemented. The problem with some of them is that, while they were interesting when they were offered and could make a positive contribution to the game, they are now somewhat out of date with respect to the developer's design philosophy. One of them, perhaps the most interesting of all, is the creation of a champion entirely based on his pet. The idea was that this companion was permanent and could be controlled by the player.
Riot Games discussed this character and others on the now-defunct official community forums. The developer bought into the idea of creating a champion who would have a meaningful relationship with their animal and live with them rather than occasionally summoning them. We're not talking about an Annie-type character that can bring a bear into Summoner's Rift or something like Kindred, although the character is considered a champion with two entities (wolf and lamb). The character in question had to have a controllable companion that the entire skill set revolved around.
Whether due to the design challenge or the lack of technology to implement it properly, the truth is that Riot Games has shelved this idea. An unnamed character who faded into corporate history who we never heard from again and who practically became a ghost in Riot Games history. In fact, characters who possess a companion are becoming less and less common. Almost every notable character in this genre appeared in the early years , and while Bel'Veth introduced a similar mechanic, it's more of a different hive idea also mentioned by the devs.
It seems virtually impossible that Riot Games will ever decide to introduce such a mechanic. Champions with one or more companions have always been problematic for the game. Yorick is one of the buggiest characters, Marguerite doesn't always respond as one would expect when playing Ivern. For now, we'll have to stick with Orianna who, using all of her abilities on an object outside of the champion herself, is the closest thing to this idea.