Many demons and Warlocks attempted to destroy the princely ghost during their occupation in Stormwind, however none of them made it out of the castle alive.
As a ghost, Anduin’s emotions are amplified. He can easily get overwhelmed, succumbing to the feelings of anger and sadness so much that he can’t feel anything else for days.
After every emotional episode, he’s left drained and with the lingering feeling of shame for his actions. Another effect he suffers from is the constant pain of his fatal wounds. These are what usually send him spiraling into an emotional episode, as they tend to trigger a vivid flashback to his death and get him all worked up again.