Meshuvel

Meshuvel was a female planeswalker who encountered Urza when he was new to his powers, and trained him to use his nascent abilities. She then tried to trap him in a time well out of fear of Urza's eyes. Her attempt failed, and she planeswalked away in terror. Urza wanted to find her, not to get revenge on her but out of curiosity as to why should we act as she did.