The ancient Desolate Beast was originally slumbering in the Return to Ruins Abyss. First disturbed by a few tiny insects, and then struck by a drastic upheaval of heaven and earth, it was jolted directly awake, naturally arousing an inexplicable fury.
No one who is fast asleep and rudely disturbed would have a good temper.
Let alone an ancient relic like a Desolate Beast, which operated almost entirely on instinct.
Chapter 359