Why is Riolu considered a baby Pokemon?

I know it’s in the undiscovered egg group, and I know it evolves from Happiness, but that’s it. Unlike all the Sinnoh babies, it doesn’t need incense to be bred from a Lucario, and it doesn’t meet the definition of a baby Pokemon; a lazy, smaller, weaker Pokemon added to the beginning of an evolution line at least a generation after the first Pokemon’s creation.

Pleaselog inorregisterto add a comment.

Specifically, baby Pokémon can be classified by the following criteria:Must be obtainable by breeding.Must be the lowest form in a family chain and must be able to evolve at least once.Must belong to the Undiscovered Egg Group.

sourceThere’s nothing in there about “lazy”, “small”, “weak”, or being introduced after its evolutions.

Your definition of a baby Pokemon is totally inaccurate. Baby Pokemon were introduced in gen 2, and BTW Togepi was the first ever obtainable baby Pokemon, and you wanna know what? It was introduced alongside Togetic, just like Riolu was introduced alongside Lucario! Also in sumwuns source(Along with their bullet points), it said,

Baby Pokémon (Japanese: ベイビィポケモン baby Pokémon) are Pokémon at the lowest stage of Pokémon Evolution that cannot themselves breed.

Anyway I hope this helps you understand why Riolu is a baby Pokemon. Also, no source ever said this, but baby Pokemon can’t be legendary.

Source: My common sense, and Bulbapedia