nice work, that definately fixed the un-numbered series so it doesn't end up in the title, but there's a weird side effect. in the {Series} field when i input this for example:
Bunch, Chris - Legion 01 - The Last Legion
this is what comes up in the {Series} field:
Legion 01 [1]
when i input this:
Bunch, Chris - Legion 02 - Firemask
this comes up in the {Series} field:
Legion 02 [1]
notice that the numbers are outside the brackets and the 1 appears in all of them in the brackets. this happens to all of them in the series.
this is what it looks like with the prior regexp:
Legion [1]
Legion [2]
other than that it's perfect. it is a little annoying, but it's purely cosmetic. whereas earlier when i input:
Bunch, Chris - Legion - Firemask
this is what pops up in the {Title} field:
Legion - Firemask {Title}
notice that i left the number out this time? this keeps the metadata from automaticaly downloading, and i have to get in there and delete "Legion - ". hence, not cosmetic

your revised regexp makes that same filename pop up like this:
Firemask {Title} Legion {Series}
but again like i pointed out earlier, if there is a number in the series (which there usually is) then i get this "[1]" next to every series name and number. it's always "[1]".