I've noticed that it seems like the only way to kill the Leveler is to cut off his head. Look:
2nd Era Leveler: Beheaded
3rd Era Leveler: Drawn and Quartered (which almost always involves removal of the head. Anyone seen Braveheart? =)
4th Era Leveler: Body destroyed by fire. Yeah, his body was - mb the head didnt burn. This is the weakest evidence but the head could still have been seperated - it fits
Moagim: Beheaded (see below)
Balor: Beheaded
Now, given that the general formula for killing the leveler is
a) Trick him
b) Behead him
c) Try to get rid of the still-living head
we can assume that a mysterious *still-living* head buried under thousands of tons of sand and rock (why? DING DING DING DING! To get rid of it!) way out there in the Barrier under what used to be Muirthemne (perhaps the term "buried under tons of sand and rock" could even mean that it's way down in the catacombs themselves) is in fact a former Leverer. (because [a] it was tricked, [b] it was obviously beheaded, [c] it's still living and was gotten rid of) And given that Balor / Connacht defeated Moagim, and the Head seems to be an old enemy of Connacht, the only logical conclusion is that the Head is Moagim.
Anyone care to offer a rebuttul?
-Ares