It can seal the King of Darkness' handpicked generals when he's powering them. If they're cut off from that connection, it can kill them.
The most powerful source of light magic in the entire world is the females of the royal bloodline. The sword is one of the tools that can bolster the princess when she's been terribly weakened to seal the King of Darkness back up again.
Nothing can fully kill the King of Darkness or the light that fuels the royal bloodline. Both sides have been trying for longer than written history.
Relics like this sword are usually the deciding factor in these conflicts. There's a few relics greater, its why it has unique powers over relying on pure light, but those have a tendency to get lost for a while and resurfacing when things are the most dire.
Re: Action
The most powerful source of light magic in the entire world is the females of the royal bloodline. The sword is one of the tools that can bolster the princess when she's been terribly weakened to seal the King of Darkness back up again.
Nothing can fully kill the King of Darkness or the light that fuels the royal bloodline. Both sides have been trying for longer than written history.
Relics like this sword are usually the deciding factor in these conflicts. There's a few relics greater, its why it has unique powers over relying on pure light, but those have a tendency to get lost for a while and resurfacing when things are the most dire.