Why do you spell Serra's name so strangely?

My husband and son have enjoyed playing the game Magic: The Gathering for several years.  My favorite card has always been that beautiful warrior, Serra Angel.  So, my tough little girl became Serra!  I borrowed this image from the Wizards Of The Coast website.

I recently had the pleasure of finding an Alpha (first edition) Serra Angel card signed by the artist, Douglas Schuler.  I used a photo of Serra as my background to frame the card.  Here's a photo of the final product.