The Heavenly Ancestral Snails are not Demons, Heavenly Beasts or Longevity Spirits, but a completely separate race. Once upon a time they were an all-mighty race capable to slay gods, but then a great calamity happened. Most of them were killed, while those who survived were sealed with 18 cursed shackles that restricted their power. They needed the Eighteen Solutions to unlock the shackles and regain their original power.
Because of this the Heavenly Ancestral Snails had always searched for the 18 Solutions, but only Calamity God unlocked all 18 shackles. It made him so powerful that only Immortal Emperor Min Ren was able to defeat him.
The Heavenly Ancestral Snails are giant snails a size of a small mountain. While being a snails they had hands and know how to speak.
The Heavenly Ancestral Snails possess several innate abilities:
The Eighteen Solutions are the main source of the Heavenly Ancestral Snail's strength. They are not a technique, nor a profound truth, but True Fate Solutions (真命之解) - keys to unlock 18 cursed shackles of their Race's Calamity. The more shackles are broken the stronger the Snail become. Once freed from all 18 shackles, Heavenly Ancestral Snail would be able to slay even gods.
It is unknown how much strength every Solution unlock, but Niu Fen with 6 Solutions was at least comparable or even already stronger than Ancient Saints, and was forced to seal part of his strength before entering the Evil Infested Ridge.
The Heavenly Ancestral Snails has two bodies - main one of a giant snail, and a second human-like body. They can freely transform from one form to another.
In their snail form the Heavenly Ancestral Snails can move as fast as lightning. Moreover, they could move in complete silence or be extremely thunderous; it is completely under their control, and no matter the chosen style, the speed remained the same.