The Aka ≈ 'Zarr connection is so mainsleeve, let's be intolerable CHIMsters and try and proscribe more some alternative Chiral partners amongst the various powers of the AURB. And remember, the more obtuse and byzantine you are, the more interesting knots we can twist the ingame-is-canon-law-because-that's-how-other-IPs-function crowd's panties into.

My personal take:

Julianos ≈ Xarxes

Kyne/Kynareth≈ Jephre

Tsun/Zenithar ≈ Trinimac

Magnus ≈ Dagon

Parthurnax ≈ Morihaus

Agdistra ≈ Vekh

Dibella ≈ Nocturnal

Arkay ≈ Phynaster

St. Jiub ≈ Valen Dreth

(disclaimer: I'm half-serious, naturally. So be sure to have a sense of humor before you try and roast me over your flames.)

Barenziah - Boethiah?

Sanguine ~ Dibella
The Divine Crusader ~ The Eternal Champion
Blodskaal ~ Duke of Mania-Dementia
Periff ~ Berry

... edit, I think I missed the point with the last three above. Not so much opposite halves but different faces of the character role. Blah.

Robust, oily muscled men ~ Hircine
Mara ~ Azura

---edit2
I meant the Heroes whom Hircine chases as Prey. Prey and Predator. That's sort of the same-coin-thing going on.
And now I'm laughing. Robust, oily muscled men are Prey. Hahahaha [...]
lol typos

edit3--
Also,
Sheogorath ~ Dibella. The gods overlap, don't they. What with the 16+ :: 8 ratio.

Oh mara/azura. Genuine concern versus all the strings and catches.

Auri-El ~ Sheogorath

Syrabane ~ King of Worms

Riddle'Thar ~ Mantella

Magnus ~ Seht

Umaril ~ Rajihn

Pelinal ~ Numidium

Morihaus ~ The Hist

Cyrus ~ Baan Dar

Lunar Lattice ~ Chim-el adabal

Half of them are 'goraths.

Tharn/Mankar is too obvious, but Tharn / Lorkhan?

Oh I'll bite. TES takes ingame-is-canon further than any other IP - it is this fact united with how the ingame lore from different games (and often in the same game) will contradict eachother (itself) so explicitly that we get the wonderful spaghetti-mess that is The Elder Scrolls. That in mind, let's do this like Theodore the Studite:

Azura ≈ Kyne
Alduin ≈ Ysmir/Talos/Dovahkiin
HoonDing ≈ Herma Mora
Mehrunes Dagon ≈ Uriel Septim VII
Hasphat Antabolis ≈ Lorkhan
M'aiq The Liar ≈ Lorkhan
Divayth Fyr ≈ Lorkhan
and of course
Vehk ≈ Vehk

My personal favorite pulled from my long-thought extinct mind bank of lore ruminations:

Champion of Cyrodiil ~ Akatosh

...and the return of the prodigal thorn in my side:

Talos ~ everyone

Vivec~Mara