Bill why is it that pokémon such as Rotom and Spiritomb are not considered legendary pokémon but the Cosmog line are? I used to think that a pre-requisite for legendary pokémon was not evolving, but you can’t say that there can be only one because two different Cosmogs have been identified. Is there even an official way of figuring it out?

Actual rarity and power levels, anonymous. While it’s true that it’s incredibly difficult to find spiritomb and rotom in the wild, neither are so rare that they’re considered mythical or actual cryptids. In fact, spiritomb alone is actually quite common, assuming you can find a an odd keystone (which is uncomfortably common in the highly spiritual Sinnoh).

Likewise, neither pokémon possess abilities on the same level as true legends or even mythical pokémon. While, yes, cosmog and cosmoem technically possess power levels much less potent than rotom or spiritomb on the battlefield, both members of that line possess unique, reality-warping abilities off the battlefield—abilities that rotom and spiritomb and other particularly rare species can only dream of possessing. And then, of course, there’s the fact that cosmog’s final evolutions possess power levels that are far more potent than that of most other pokémon species, so that, in combination with cosmog’s natural abilities, simply sets it apart from other pokémon.

In short, it’s not so much rarity alone, anonymous, but rather rarity and what a pokémon can do that form the litmus test of what is and isn’t a legendary.

Cosmog and Cosmoem

Cosmog
The Nebula Pokémon
Type: Psychic
Official Registration #: 789
Entry: This strange, nebula-like pokémon possesses a body made entirely of gas, and as such, it’s said to be physically frail. On the other hand, it also possesses incredible powers, such as the ability to open portals to strange and wondrous dimensions. It is either because of its composition or this ability to teleport that causes it to be highly difficult to capture, but either way, it is strongly recommended that you do not put it in a bag.

Cosmoem
The Protostar Pokémon
Type: Psychic
Official Registration #: 790
Entry: The evolved form of cosmog, by battle experience. After enduring incredible hardship, cosmog undergo the process of evolution, whereby its entire body mass becomes highly compressed. In truth, its nebulous body is really the very core of the black sphere at its center, while the rest of its appearance is really added matter that forms a solid cocoon. Consequently, the resulting cosmoem is extremely dense. Needless to say, it’s also not recommended that you put this pokémon in a bag, but in cosmoem’s case, it’s less because of its ability to escape (which it no longer has) and more because when the author says that this pokémon is extremely dense, he really means it weighs well over 2200 pounds.