The forest of Terror Of Ranvier started from low land to a highland area which was followed by mountains.
The reason it was named Terror Of Ranvier was centuries ago, the Western Front was called Ranvier and anyone who was caught in this place would find themselves terrorized by the ferocious wildlife and the vast and deadly wilderness.
After Kinley occupied the Western Front due to various struggles, the beasts were eradicated and their numbers became quiet but the long-standing forest with rugged mountains could still kill some if they were trapped here without any prior knowledge.
The rugged mountains and blinding darkness were factors which didn't let anyone even see the inch.
They limited the movements of both sides but since the reserve units had been trained in a place like this for a month, they were able to move freely.