The leader, Blue, is at Cinnebar Island. To get him to return, you have to beat all the other 7 Gym leaders in the Kanto region. PS you have to talk to him after you've beaten he 7 others before he returns.
I think you need to beat 7 kanto gym leaders to fight him.
The gym leader is Giovanni, leader of Team Rocket. You have to come back to Virdian last as he is the Eighth gym leader. THE LAST ONE!
*SPOLIER* , Giovanni ,
the gym leader is... Giovanni the head of team rocket.
cinnabar island. he will go to the gym after getting all the 7 kanto gym badges
you find Giovanni in silph co.
It is the last gym. You should have 7 badges to battle the gym leader. The gym leader is Giovanni.
You head to Pewter City and battle Brock there gym leader! Then from there you head south to Virdian City. There gym leader won't be there so you keep on to Pallet Town. Then pass Cinnabar island and head to the seaform island and challenge the gym leader! Then after you defeat there gym leader talk to the Virdian Gym leader at Cinnabar island and then you go defeat him at his gym
go south from pallet town and go to cinibar island there will be the 8th kanto gym leader but you need 7 gym badges to get him back to virdian city so you go to seafoam islands(east from cinibar in the sea) and go up the ladder then you will fight blaine he has fire type Pokemon then go back to cinibar and show blue(8th gym leader)then go back to virdian city and challenge blue
Its in virdian city. The gym leader is Govanni, and he uses ground and fighting pokemon.
after you get all 15 badges go to cinnabar island and there will be the 16th gym leader after you talk to him go to the virdian city gym and he will be there
go to cinnabar city you'll see somebody talk to him he'll tell you He's the gym leader for virdian city you will see him at the gym after that