Secondary Nature—Mammoth Home!
Mud Vipers were extremely territorial in nature. Though being Beginner Iron Grade Pranic Beasts, frightened by powerful Pranic Beasts, when their nests get damaged, they charge at the enemy with reckless abandon.
It was why the First Minor Crisis happened, even though Mud Vipers are afraid of Empyrean Tusks the most among all Pranic Beasts.
Bone Vipers were created from them, with their Nest being replaced with the Empyrean Tusk's body. Basically, the Empyrean Tusk was their home, so they would do everything in their power to preserve their home.
And if the slightest harm were to come to their home, they would charge out and target the cause. By harnessing their genetic desire to protect their homes at all costs and by linking it to their Prana, Grehha managed to create their Secondary Nature.