~SPOILERS for Twilight Princess Bosses~

In the Arbiter's Grounds, you enter an empty room, except for a lonely dark sword imbedded into the floor with several talismans attached to it. You cut one off. It awakens and starts to glow and floats into the air.

Midna tells you to turn into Wolf Link to see what the big deal is. You turn on your wolf senses, and discover that Death Sword has a spirit holding the sword. Unless the spirit is the spirit of the sword. Not sure, it's never specified and left a mystery. He was creepy and scary!

In the Snow Peak Ruins, You go look for the mirror shard. Yeto is making soup for his wife Yeta. She's been sick. But once you've cleared the dungeon, you finally meet up with Yeta and she leads you to the Yetis' bedroom to show you the mirror shard that Yeto gave her...

Yeta gets possessed by the mirror shard. She turns around and screams at Link that he can't have the mirror shard! All the windows in the room shatter! Ice and snow fill the room. The Ice encapsulates Blizzeta inside - creating a giant iceberg. Poor Yeta. Being turned evil by the mirror shard. At least after the boss fight she turns back to normal. But that face she made when she got possessed was really scary!

The boss fight was very unique, you had to look down at the reflected ice floor to see where Blizzeta will attack you and you try to evade her attacks.