Timothy is a very powerful and skilled Pokémon Trainer with a vast number of pokémon at his disposal. Being able to use any pokémon with expert experience even those that don't belong to him make's him a very tough opponent to beat. He is also known to breed and raised a large number of pokémon, this includes his Nina, Nikita, Articuno and a variety of other pokémon making him one of the top pokémon breeder's in the world. Also he has been known to have created and cloned a large number of pokémon as well, this also includes his Nina, Nikita, Articuno, and a couple of his other pokémon.
What is weird though is unlike most trainers that are only able to carry 6 pokémon max with them Timothy is able to carry more pokémon with him. Even though Kachu, Nina, and Nikita are Timothy's pokémon and they each have a pokéball of their own he is able to keep all his pokémon with him, though how he does this is unknown.