In his gym
Blaine is the gym leader in Cinnabar Island. When you get to Cinnabar Island the door to the gym is locked, you need to go to the Pokemon Mansion to retrieve the key. Once you have it you get to the gym and battle Blaine to get your seventh badge.
seafoam islands; 15th gym
Blaine.
To get to Blaine, he is on cinnabar, but the last gym leader... He is in one of the towns once you defeat Blaine, I think it was Viridian or Vermillion. =)
volcano badge
Blaine's gym is in the Seafoam Islands
He doesn't rebuild his gym. He moves to the Seafoam Islands.
Blaine's Gym is in Mahogany Town.
The seventh gym (Blaine's) used to be on Cinnabar Island. After the town was destroyed by the volcano, Blaine has relocated his gym to the Seafoam Islands. Just Surf east of Cinnabar, and you will reach him.
blaine is a fire type gym leader and is located right of cinnabar town so I suggest u use maybe a water type and/or a ground type
the last gym leader is Blue.When you go to the seventh gym leader Blaine you should see Blue and asks you if you have 7 badges then you beat Blaine and go to Blue and he says to meet him at his gym