Where do "Mort" and "sto-helit" come from?
Well, in most web communities it's usual to use a nickname. Since I didn't have one in real live, and didn't like to use my plain boring realname, I was "forced" to find one...

Since I like Terry Pratchett, I wanted to use a person from his discworld. Mort seemed quite a good choice. He's got a dark, mysteric touch (since it's French for "Death", and still contained in words like "mortal"), but isn't as clichee as "Death" itself. Well, at least in English and German. With "Death" or "Tod" (Geman), also less people would see the connection to the discworld, and I didn't indent to be associated with an evil "Grim Reaper".

Mort (or rather "Mortimer" -
but that's of course just to get the nickname) appears in the book with this  title. He's a guy that's a bit clumsy, and Death takes him as apprentice. That's because he likes to make a match between Mort and his adopted daughter Ysabell (Death just couldn't let her die...). Well, you'd better read the book yourself, it's really good... (Though I like it's successors "Grim Reaper" and "Soul Music" better...)

Sto Helit names both the capital and a duchy in the Sto Plains, an area Mort is made duke of at the end of the book. By this, it also became their last name, which was inherited to their daughter Susan, who later on appeared more often in books.