Main villains of each main game?

[MidbossVyers]

I know that the main villain of ESI is Jagar Tharn, the main villain of ESIII is Dagoth Ur, the main villain of ESIV is Mehrunes Dagon, and the main villain of ESV is Alduin. Who was the main villain of ESII: Daggerfall? Don't say that it was either of the lich kings because they are more evil faction quest givers than villains. Speaking of the lich kings, according to http://www.uesp.net/wiki/Lore:Zurin_Arctus the Underking writes the Hero a letter asking for the Mantella. I recall that the Worm King also writes a letter asking for the Mantella. First of all, am I remembering correctly? If so, where can I read it? Also, do any of the mortal kings/politicians who want the Mantella write the Hero a formal letter?

[AKB]

If it wasn't obvious, the main villain of Daggerfall is clearly the postal service. The honest answer is that there is no specific main villain, just characters with different motives. You can see the letter he wrote on the article you linked, in the Notes section. I can't find the rest on the site, although the others write letters as well, I also can't find them in the game files.

[MidbossVyers]

Thing is, I do recall a letter written by Mannimarco the King of Worms (he says that the only reward that he can offer is fame, etc.), but I can't find it.

[legoless]

I remember reading Mannimarco's letter as well, but it doesn't seem to be on the wiki. Daggerfall didn't really have a main villain, but the Underking was definitely a protagonist of a sort. He was supposedly responsible for all the monsters you see about, as well as some other stuff I can't quite remember... Just because he's nice enough to send a letter doesn't mean he's a good guy. If you give him the Mantella, he blows himself up and makes an anti-magic zone. He's also on the front of the case.

[Dark Spark]

Villains and heroes are character roles, while antagonists and protagonists are storytelling roles.

[MidbossVyers]

I'm not sure how canon this is, but http://elderscrolls.wikia.com/wiki/Lett ... Mannimarco

[AKB]

You can see all of the letters here. We need to extract a few things from Daggerfall game files that were not part of the scope of the UESP when the Daggerfall section was made.

As the linked to article shows, most of these are fairly insignificant/generic, and these were the letters for the penultimate quest, probably explaining their exclusion.