Mehrune is evil
Molag Bal is disgusting...

Neither. Molag Bal is clearly some combination of the gods Moloch and Baal, and Dagon is after the Summerian Dagon, or maybe the Lovecraftian one (same difference, really). The Christian concept of devils is not really well represented in any modern media, i.e. with horns and tail and all that. And various Christian denominations have their own spin, depending on the country, particularly within Orthodoxy.

If we compare TES lore with media like the Divine Comedy or Paradise Lost, which even those are a departure, there's practically no similarity anywhere, except in the most superficial sense of good=good, bad=bad.

A lot of the Aedra and Daedra in the game were named after the original devs, mind you. These two maybe weren't, but it's worth considering that they could just be the characters one of them developed. Like Theodore Peterson is Sheogorath, Julian LeFey is Julianos, another lady dev was Mara, etc. I don't know if ALL the Aedra and Daedra have their dev equivalents, but it's possible.

Out of the two I voted Bal, but the role of adversary varies a lot from culture to culture in Tamriel.

Some version of Lorkhan is often involved, but he's not an active player so the anaology falls apart there.

Lorkhan would also be a contender according to many in lore sources. Though I think he is a closer match to the demiurge of the Gnostic belief, still Christian however.

Molag Bal seems way more like traditional devil/Satan to me, mostly because of the eternal torture and suffering thing.

From the UESP pages on Dagon and Molag Bal:

''Mehrunes Dagon (formally, the Exalted and Most Puissant Lord, Gerent of Dagon, Mehrunes,[1] also the Black Daedra Lord,[2] Mehrunes the Razor, Mehrunes the Thieftaker, Mehrunes Godsbody, and Mehrunes the Red Arms That Went Up)[3] is the Daedric Prince of Destruction, Change, Revolution, Energy, and Ambition.[4] He is associated with natural dangers like fire, earthquakes, and floods.''

''Molag Bal (Stone-Fire,[1] or literally "Fire Stone" in the Aldmeri language) is the Daedric Prince whose sphere is the domination and enslavement of mortals.[2] His ultimate desire is to harvest the souls of all mortals and to bring them within his sway by spreading seeds of strife and discord in the mortal realms.''

The bolded portion is a key reflection of the Christian devil, whether intended by his creators or not. As someone who grew up intensely Christian, the motifs here are obvious

Nairinhe wrote: »

None?

i have to go with that ^
im not sure what the OP is looking for in the term "Christianism", because that term seems to lead more into political references.
but as far as Christianity, there are some similarities in small ways that are not as noticeable, but, those ways are too small to have any real strength in reality to the Christian Faith, there really is no complete and obvious comparison to Satan in all of elderscrolls titles that i have found.

well, i withdraw that slightly for the situation "Neravar" is put in, because that would fit Satan very well, or atleast what looks like satans position, being as Satan comes as a Power of false righteousness and light acting as truth and love when there is none of those powers within him, and also acting as God in Vvardenfell. would be the closest i could think of in all of nirn and es titles, but you are here in the OP only asking about Mehrunes Dagon and,
Molag Bal. but again i must admit that only Neravar could fit "kindof" the role in all of es titles he would be the closest, but that's not what was intended "atleast it Looks like that was not intended" for his character in Vvardenfell. ofcourse it could be debated heavily with peoples differing opinions of Satan and christianity.

Could also throw in Clavicus Vile, Boethia, and Mephala in this poll and they'd fit to.

As many others have said, ESO doesn't have a direct Christian equivalent. However if the poll only points to Molag Bal and Mehrunes Dagon, I'd say Molag Bal is closer to the Abrahamic/Judeo-Christian personification of Satan/devil.

If you read the lorebook The Book of Daedra, it says "Molag Bal, whose sphere is the domination and enslavement of mortals; whose desire is to harvest the souls of mortals and to bring mortals' souls within his sway by spreading seeds of strife and discord in the mortal realms."

According to Judeo-Christian theology, Satan (a.k.a. the Devil) wants to dominate humans and enslave them to their addictions and thus reject God. Satan will try to spread discord and strife by creating doubt in humans. I'd say that based on this belief, Molag Bal would be the likely candidate to hold the title of "Devil" based on a Christian perspective.

ESO follows a polytheistic view and therefore all the Daedric princes will resemble a god from various real life pantheons. Such as Mehrunes Dagon comes from a combination between Dagon in ancient Canaanite pantheon but also resemble Shiva in Hinduism. However, there are some sources that say that H.P. Lovecraft inspired many of these Daedra.

I posted this somewhere else in cyberspace:

Anu in ESO - http://en.uesp.net/wiki/Lore:Anu
Anu in real life - https://en.wikipedia.org/wiki/Anu

Azure in ESO - http://en.uesp.net/wiki/Lore:Azura
Azura in real life - https://en.wikipedia.org/wiki/Azura_(religious_figure)

Daedric Princes in ESO - http://en.uesp.net/wiki/Lore:Daedric_Princes
Angelic Princes in real life - http://www.archangels-and-angels.com/misc/sarim.html

Bal in ESO - http://en.uesp.net/wiki/Lore:Molag_Bal
Bal in real life - https://en.wikipedia.org/wiki/Baal

Auri-El in ESO - http://en.uesp.net/wiki/Lore:Auri-El
Uriel in real life - https://en.wikipedia.org/wiki/Uriel

Yes there are Daedras that look like demons but there is actually a demon creature in Cyrodiil that looks like a wyvern. Not to divert from the OP but evil Daedras are not demons?