Experience/Core series/Relation to level/Slow

The final of the four Generation I experience groups, the Slow group features the highest amount of experience required for a Pokémon to reach level 100 in Generations I and II, and the second highest amount since then. Containing many rare, powerful, and Legendary Pokémon, Pokémon in this group are typically very hard to raise; all pseudo-legendary Pokémon, by definition, are in this experience group. At level 100, a Pokémon in this experience group will have 1,250,000 experience points.

For a list of all Pokémon in this group, see.