So, I was watching a highly edited video of someone destroying the Dark Brotherhood and in the comments (it was a highly rated one before YT changed with the Google+ crap), I've read that wiping out the Dark Brotherhood somehow... helps the Thalmor due to the fact that the DB worship Lorkhan via Sithis.
Am I missing something here (seriously, let me know if I am)? Of the lore I've read, I've never read anything noting that Sithis and Lorkhan are aspects of the same deity (ex: Sithis/Padomay, Kyne/Kynareth or Talos/Ysmir). The only thing related to any links is that Sithis presumably created Lorkhan to destroy the universe after the Aedra "enslaved" everything he created and even that info is questioned.
Even so, I fail to see how it would help, or hinder the Thalmor in anyway if the DB were completely wiped out (bearing in mind that Babette, Cicero, and the Night Mother aren't there when the attack happens by the Dragonborn).