Is Deoxys one Pokemon or four?

Question

Deoxys has 4 different forms, I was wondering if it is still a single Pokemon or if it is multiple. Applies to all Pokemon with multiple forms, not including mega evolution.

Answer 1

Almost all Pokemon with multiple forms are counted as one Pokemon. This includes gender differences like Meowstic-M and Meowstic-F, form changes like Deoxys, and even type changes like Arceus. This can be proven by going into the National Pokedex, which clearly classifies different forms as one Pokemon. There are two exceptions to this:

Exception 1 is regional forms. While they're technically the same Pokemon as classified in the Pokedex, they are typically different enough to be considered their own Pokemon. This is chiefly evident in (Galarian) Meowth, Mr. Mime, Corsola, and Yamask, and (Hisuian) Sneasel and Qwilfish, as all are able to evolve into new Pokemon that their original forms cannot.

Exception 2 is the Nidorans. Due to limitations at the time, the Nidoran forms occupy two entries in the Pokedex. While by modern standards they would be considered mere gender differences, they are technically two separate Pokemon.

Tl;dr Deoxys is 1 Pokemon with 4 forms.

Comments

Just to add to this, it may be helpful (if you like watching movies and what not) to watch the Pokémon movie Destiny Deoxy's. In there it clearly shows Deoxy's transforming from one form to another. I don't know where to find the movie specifically, but somewhere on the Pokémon website you'll find the movie.