>>21213092Bulbasaur is the First in the Kanto Dex, which as Oak is the proginator of all Pokedexes, the Kanto Dex became the basis of the National Dex, resulting in Bulbasaur being the First in it. This is solely since Oak decided to put Starters at the, well, Start.
Rhydon, in our world, was the first one created in terms of concept design.
Mew has no special place as First, it simply has a wildly mutagenic DNA sequence that contains literally every other Pokemon's DNA within it. Whether this is due to being a primordial soup of Origin, or by otherworldly design, is yet unclear.
Arceus, for those who belive him the Creator, would be the First in Existence, and from him spawned all other Pokemon. Popular theory has Mew being a genetic backup of sorts. Others who think Pokemon are a spaceborn race would hold that Mew is a Seed of Life Arceus sent to the planet to propagate the Pokemon form.
Others see Arceus as just another Pseudo-Deity whom legends exist about, but otherwise holds no special status as a First. Still others believe the visible Arceus is but an Avatar, with the full being being never to be seen.
Without further proof, Arceus may or may not be the true First, and without further scientific evidence Mew may or may not be the true Source. All that is definite is that Mew contains all other genetic sequences, but that could be by acquisition, rather then mutation.
