The Dark One Actively forcing his power into the realm

new name here for these fissures

a Fissure of dark magic, and a spawn point of corruption

spawns:

• Bale
• disease
• fog
• more corruption
• dark magic

Around a fissure you would see more violent growth / malgrowth

These would start as a small splits in objects or the earth with rich tendrils crawling around it, emanating black smoke, dark magic, and some small dark creatures

If left alone, or if catalyzed by ritual or other means, it will grow, allowing for more vicious and large creatures, magic, and corruption to spew forth

These can appear by themselves in small cases, or they can be created, with the help of an acolyte, or other source of dark magic, like an artifact or other item.

Ritual, offerings, or other dark magic practices can accelerate the speed that these grow.