As for the Brecilian Forest, the Orlesian bard, Leliana, said that "People have always spoken of dark and mysterious woods, haunted by unseen beings. The Brecilian Forest is one such forest. They say the Veil is thin here and spirits from the Fade pass over, drifting through the trees and giving them an unnatural and sinister intelligence. It is said that if you feel you are being watched in the Brecilian Forest, you are." Source: [link]
The “deer” are called “Halla”. No creature is more revered by the Dalish than the halla. No other animal has a god of its own. These white stags are much larger than ordinary deer, and the Dalish halla keepers carve their antlers as they grow, making them curve into intricate designs. In ancient times, these stags bore elven knights into combat, but since the fall of the Dales, they are used less as mounts and more to pull the aravels (The Dalish are nomadic- this is the name they have given to their caravans). --From Codex Entry: Halla (Edited) Source: [link]