thoughtsbeyondwords
you get him at the end of the world of balence if i remember correctly. i know the last thing you do in the world of balence cept for hit "A AA A A A A" is say wait five minutes or leave now. wait to get shadow leave to uhhh let him die i guess.
Wee I have not posted here in a while!
Anyway, there are several points in which shadow joins you before become a perminant addition to the party in the world of ruin.
His first appearance is in South Figaro when you travel there with Locke and Edgar. You see him entering the Cafe, and if you approach him inside, the naming screen pops up.
During the 3 scenarios when the party splits, after the first fight with Ultros you can get Shadow to join for a while in Sabin's journey by speaking to him at the hause of Gau's father. Though he leaves again before you jump over the falls with Cyan, on your way to getting Gau.
Later, after you travel beyond the mountains using figaro castle in your search for Terra, Shadow can be found in the cafe at kohlingen. If you purchase his services he may remain in your party all the way up until the point you rescue terra.
After this he is not seen for quite a while, but when the returners agree to help the emprie search for the espers, it turns out Shadow has been hired to come along. He will remain in your party until you retire for the evening at the inn. Later, he saves you from a burning building.
Here you travel to the holy place where the espers have gathered, but shadow does not accompany you. When you return you are betrayed, General Leo is murdered, The Espers are defeated, and Ghestal and Kefka raise the floating continent. You come across interceptor, wounded and limping, and masterless. It seems at this point that Shadow too has been killed.
Upon landing on the floating continent however, you find shadow is alive. He will join you, but leave again before the confronation with kefka. Then as things seem their worst, shadow shows up to stall kefka while you escape. You make your way to the end of the continent to the airship waiting below.
Here is a pivotal moment, you can save yourself, or, wait for shadow. If you choose to wait, he will appear at the last moment and you all leap to saftey, for a moment.
The world is ripped asunder and the heroes are scattered to the winds.
During your travels in the world of ruin, you may return to the veldt where, deep in a cave, you come across the battered body of shadow. He is taken to thamasa to to heal. But disapears again.
The final appearence of shadow is in the dragons neck colloseum. He will remain there until you wager the item he seeks, and he will fight you for it. When you defeat him, he joins your party for the rest of the game.
And that, as far as I can remember, is every appearance of shadow in ffvi.