Once you catch all of the Uknown, you can go to the town with the day care and go to one of the houses and trade them in for letter seals. other than that they don't unlock anything.
catch all the unknowns
nothing you just have them
nothing
you can read the unknown and you unlock ? and ! unknown
You catch unknowns.
in the ruins of alpha after you solve the puzzles
yes in the Solaceon Ruins
read the wall and catch all the unknowns
You dont get arceus sorry
id say unknowns ive caght at least 5 different unknowns that r shiny
every letter in the alphabet is a unkown and ? ! are unknowns
There are 26 unknowns out of 486 Pokemon. There are actually 28 with the ! and ? plus the English alphabet and there is 493 not 486 geez Lolz