The strongest (most powerful) Pokemon is of course rayquaza.
Easiest way to find stronger Pokemon have a decently strong Pokemon first in your party use repel stay in a area and maybe a Pokemon stronger than you will show up.
They don't get sronger, but your Pokemon will get stronger if you battle them a lot.
arceus
Train your Pokemon and level them up by battling.
yes they are
yes because arceus can be any type of pokemon
brick break
I believe X is stronger, but Y looks cooler.
When used on a pokemon it will boost its level and make it stronger.
That is a matter of opinion and skill. The higher the level, the stronger, and the better the Pokemon, the stronger. In the end, it all comes down to stats and opinion. So there is no real known best or strongest Pokemon.
There is no such Pokemon as Mewthree.
Sceptile