Acnologia (アクノロギア Akunorogia) was a Dragon and the divine guardian of the hidden land Montes Secreta, whose name was taken by the Dragon Slayer Acnologia as an act of spite towards his race's evil doings.
Acnologia was an off-white colored dragon with intricately designed fur and yellow eyes.
Before returning as an evil Dragon, he was a kind-hearted dragon who looked over his domain of Montes Secreta.
After hearing rumors of humans and dragons going to war with one another, Acnologia left to investigate the situation, only to return mutilated, scarred, and convinced that humans are petty and conniving, which led him and the other Dragons to destroy and murder the people of Montes Secreta.
- Fairy Tail Anime: Episode 326