its on spring patch by veilstone, it appears when you beat the game
You cannot find the Pokemon Darkrai in Turnback Cave in the game Pokemon Diamond. Instead you can find him in Newmoon Island.
You can find Giratina in the Turnback Cave, in the Past Room with the 3rd Pillar Chamber
No, people won't want to battle in Turnback Cave, there are no trainers in Turnback Cave.
After you beat the Elite Four, there will be a new path underneath Veilstone called Spring Path. Follow it to Turnback Cave, where you can find Giratina
After you defeat the Pokemon League and get entered in the Hall of Fame, Go to Turnback Cave on Spring Path (West of Route 214). Turnback cave is a labyrinth, but if you get to the end, you'll find Giratina (Altered Forme).
Turnback Cave In Diamond and Pearl. Torn World in Platinum.
In Turnback Cave after Spring Path on route 214 (must find in cave after many rooms)
There is a Shortcut way Turnback Cave. You go to Seabreak Path and there two way road. One leads to Turnback Cave while the Other leads to Flower Paradise which is the way you straight.
Go to Spring Path and there will be a cave that is turn back cave
You can find this pokemon, named Dusclops, at the Sendoff Spring and the Turnback Cave.
Turnback cave in Sendoff spring after you beat the elite four
At Turnback Cave