gen1 had 5 legendary pokemon gen2 had 6 legendary pokemon gen3

Sinnoh 2.0

Though to be honest I'm less bothered by this than Gen 4 because rather than just over indulgence like in Gen 4 there is actually a purpose to UBs. Also you forgot the Alolan forms.

Source on UBs being legendary?

>>29787521
I wouldn't call Ultra Beasts "Legendary". We see like 6 individual UB-01 during the game, so they're definitely not one-of-a-kind, nor very rare within their own universe.

>>29787576
Alolan forms are just recolored Kanto Pokemon. I don't think they qualify

Even then, that only adds about 18 new Pokemon because of how little Alolan forms there are

>>29787594
They're post-game mons that can't breed and have absurdly high stats. They're legendaries in all but name

>>29787623
>new skin
>new stats
>new types
>new moves
Alolan forms are new pokemon even if use old names

The only thing that makes the UBs alright is the fact that they're involved in the story. There's no random Three Musketeers-themed trio running around in SM.

>>29787521
SPOILER: Necrozma is indeed a legendary Pokémon and NOT an Ultra Beast.

>>29787659
Depends, do you consider Megas new Pokemon?

Even then, it doesn't add much. Only 18

>>29787728
Megas are not permanent (also use the same moves)

>>29787623
New stats. New movesets. New models. New animations. New pokedex descriptions. New abilities.

I mean they're based on old Pokemon but they are by all practical considerations new Pokemon.

>>29787728
Megas aren't permanent and share the same moveset, they also aren't independent from their "base forms" like Alola forms are.