he is like Bill, pokemaniac; except he is on Island 1 after you defeat Blaine on Cinnibar Island Bill is outside to meet you and he takes you to the island where he is in the building. He is working on getting the PC system in the islands connected to Kanto. Bill goes there to help him.
You get the Sapphire in ruin valley and give it to celio.
give it to celio and then mewtwos cave will be unlocked
Get past every island and then you will get the gem from a little girl on island three.Take the gem to a guy named Celio on island one.
Celio was introduced in Fire Red and Leaf Green, the Generation I remakes that included parts from Generations II and III. In other words, he is not present in the original Red, Blue, or Yellow.
Nothing to do in Ruby. Just find a ruby and a sapphire in leafgreen or firered and give them to Celio.
You can only get the dogs if you beat the game and have the national dex im not completely sure if you have to deliver the ruby and sapphire to celio to get them try to do that and if you can't then give the ruby and sapphire to celio.
beat the elite four, get the national pokedex, talk to celio on one island, get the ruby in mount ember where the two rocket grunts were, give the ruby to celio and he will give you the pass.
the Sapphire and ruby plates in leaf green are two plates that you have to give to celio to be able to find one of the three legendary dogs.
he is over in the Pokemon center on one island in front of the machine that links to Ruby and Saphire from Fire Red/ Leaf Green
In Leaf Green And Fire Red, for Johto Pokemon you need the national pokedex; this was obtained when you gave the blue and red gems to Celio in Island 1
now it is time to go to cerulean city and go into the cave that the man was blocking you from going into. and you will find mewtwo in there.
you don´t. youd have needed to go to a certain poketour. now you can only get one through cheating