I have been following along with Truegreen7's series on Youtube where he and 3 other Fakemon artists get together to design a new pokemon based on the same prompt.
This Prompt was: Pokemon Relationships. Two different species that interact with each other in some specific way like Zangoose and Seviper or Dodonzo and Tatsugiri

I decided to go with a pretty simple idea, but I think I put a lot of thought into the classic rivalry in Japanese Folklore between the Kitsune and Tanuki. Kitsune are said to be the more powerful of the two but Tanuki are more clever.
There was a story where a Kitsune and Tanuki got into an argument over who was the better illusionist. The Kitsune showed off, making many very convincing illusions. The Tanuki claims he could create an entire feudal lord's procession. Sure enough a Procession came around the corner. Believing it to be an illusion the Kitsune hopped on top of the Lord's palanquine only to discover it was completely solid and the procession was real! The Kitsune was then captured and executed.

They are also meant to represent the artistic mediums of Anime and Western Cartoons. Mainly focused on Shonen Anime and Slapstick Cartoons. Shonen tends to use a lot of flashy moves and takes itself very seriously, while Slapstick undermines violence with body morphing and is meant to be a lot more silly. They could also be a Tall skinny guy/Short fat guy comedy duo

Kitsume (Dark/Fairy type) Is a thought to be a relative of Zoroark, it can also create illusions but rather than using them as a disguise it creates Illusory effects to trick enemies and wow onlookers with dazzling moves.
Kitsume is very full of itself much like a classic anime asshole rival
(Think like Gary Oak, Seto Kaiba, Vegeta, Bakugo, Sasuke...etc)

Toonuki (Fighting/Fairy type) Is able to bend, stretch, and inflate different parts of its body at will as though it were made of rubber but rather than becoming lighter, it's strength actually grows in relation to its size and feels solid, but it can't maintain it's inflated forms indefinitely and will eventually revert to its original form. They are known for their mischief but they hate bullies and tend to get carried away delivering disproportionate justice.