>>38506763NTA but OU and UU are tiers made by smogon.
What is Smogon you ask?
Smogon is an unofficial pokemon battling community that established during Gen 3, Nintendo bans pokemon based on categories, which doesn't necessarily make for a good metagame, so a bunch of people came together to come up with their own unofficial rulesets, to make the story short OU is basically the tier 1 of pokemon in that ruleset, UU being tier 2, UU pokemon can be used in OU but not the other way around, if a pokemon is deemed to be to strong it gets banned to Ubers (tier 0), most notibly Palafin and Houndstone recently got moved to Ubers under Smogon's ruleset.
