Locations of the Spirit Forges
Spoiler Warning: Those of you who like to figure everything out for themselves may wish to skip this.
All spirit forges are secrets so finding them all will increase your secret count. It is also important to remember that, with the exception of the flay and the energy bank forges, the spirit forges can only be entered during a full moon. Activate nearby bat beacons and fly back to the forges during full moon periods.
On the same mountain where you will find the wolf there is a cave which contains the flay spirit forge.
When passing the city of Stienchencroe you will find a fork in the road with two road signs. To the west of those signs there is a two tiered ledge. The cave at the top is the implode spirit forge.
Before entering the city of Coorhagen Kain will find a decomposing corpse near an audio point. The cave next to this body is the Putresce spirit forge.
At the south western tip of the swamp there will be a ledge. Up on that ledge you will find an energy bank card. Behind that card is a mysterious crack. Use the mist form to pass through the crack and you will find the energy bank forge.
At the northern end of the swamp, to the west of the flame sword keep, there will be a cave obscured by a tree. The cave behind the tree is the anti-toxin forge.
Heart of Darkness
On the way to the Dark Eden the is a branch of the path that leads west. It is blocked by a boulder which requires the maximum strength level to push. Beyond that is a gate which opens during the full moon. to the west of that gate is the Heart of Darkness forge.
In a canyon to the south of Willendorf you can find the slow time spirit forge. The entrance is at the bottom of the canyon. Use the wolf form to jump down to it.
Pentalich of Tarot
To the west of the Nemesis Keep is the cave with the pentalich of tarot forge. To reach the nemesis castle area you must first destroy Elzevir the Dollmaker. Once he is gone the gates to the Nemesis compound will open allowing Kain to reach the forge.