Re
beat the all the gym leaders
He just disappears
to beat blue you need to defeat all kanto gym leaders then go to cinanwood he will be there
you have to beat all gym leaders in jhoto and kanto
beat the elite four.
in Ecruteak theatre
no,but zapdos is after you beat all kanto gym leaders.
yes beat all the gym leaders kanto ones too!
cerulean cave after you beat all the gym leaders
After you've beaten Brock go beat the other six leaders then you can fight Blue
after you beat all 16 gym leaders,he is at the top of Mount Silver, so talk to him to fight
when you beat 8 gym leaders professor elm gives you one.