Second Author

I recently moved from MT to WP, and when i imported my entries, it has created another author with ID=2.
Now this author is totally blank, with no username, no email nothing. I assume its password would be “changeme” but what would the username be?
The reason why i want to edit this author is that all prev posts have been created by that author, and if someone posts a comment on my prev entries, i wouldnt get a notificatiom since there is no email mentioned for the second author.
Any suggestions what i can do…? ??