Good Demigod pairs

Sedna + Oak

huge amount of interrupting ability and very high survivability. can get vicious burst damage with Pounce+Penitence or can get insane sustained damage if both have bought some Idol summons. judicious use of Heal and Shield can make the team all but completely immune to burst damage attacks. 

if we are talking 2v2 then Sedna + QoT is basically useless

Sedna lacks serious AOE unless you go Yetis. QoT is super squishy if you stun her (I know, I play a lot of QoT). Not a lot of damage output on those 2.

i think i agree Max, but on the other hand if its 3on3 i've seen some spectacular results with Queen+Sedna+Regulus. specifically AA spec reg with Wings and MotB. 

Ooze UB + Ice & Fireball TB. High damage output, huge debuff output, easy chainstuns, long stuns allowing TB to complete his combos, ability to hold lanes and push towers, both can easily get each other out of trouble, both don't need too much money to run effectively.

EDIT: Also, my guide on synergy has a lot of good tips about this sort of thing; in a game like this, it is generally much better to stack strengths than it is to spread your strengths around, especially if your strengths happen to be debuffs and stuns.

Rook + Unclean Beast. Beast can Grapple giving rook an easy hammer slam, rook can bould roll to catch someone who is running.  Both do good dps at melee.

Erebus + Regulus.  A lot of the time regulus can be dealt with, if just barely, 1v1.  Erebus with his bat swarm + 2 different snares (charm, bite) can quickly turn a 1v1 into a 2v1, into a 2v0.

Oak + Sedna: If both have priests, and are maxing out their main aggressive skills, they can be very hard to drive from a lane. Penitence + Pounce (Or, as I call it, Pouncitence) is a good deal of up front damage, and easily repeatible... even on a running enemy.

Yeah, Oak + Sedna gets pretty scary if they are both decent.  Its not real deadly to you since they arent big stare/stunners, but you arent going to kill either of them unless they really mess up.  Basically they are going to hold a lane and kill a lot of towers very fast and there isnt a lot you can do about it unless you can quickly overwhelm them with pure numbers somehow.

This combo really scares me if they are Forces of Darkness on Cataract because they can hold that stupid health flag (making them unbelievably difficult to kill) and get to your gold flag pretty quickly.  In a 3v3 there is really very little you can do about this IMO.

Vampire EB + Ooze/Spit UB. Alot of debuff and double stuns.

UB + Mine Reg. Foul grasp and Mine combo

Me and my friend run assasin erebus and spit ub, double stuns and bite. hes rollin poisoned dagger so were really hard to escape, and have lots of nuke damage

we did do reg+ub but erebus's bite stuns and bat swarm helps out alot more as a whole compared to mines and snipe

@Zechnophobe: For your Reg&Erebus suggestion: Surely ANY two demigods working together can take down 1 other demigod? I would have thought that being to take down two or MORE DGs makes a good pair.

His point is that Erebus can quickly rush in to help Regulus in a 1v1 situation as opposed to other DG who aren't as mobile. The slow on bite and stun on mass charm means that it will be extremely hard for the other DG to escape, which is something that any player with half a brain will do if they see a second DG coming at them.

Oak + Ooze UB.  Oak with Shield and minions can keep the heat off UB early game. Once the two hit level 10 or so it's a pretty powerful combo as both damage and survivability are high.  

Even better is a 3v3 with Oak, Sedna and UB.

The lack of stuns on that  3v3 team is problematic, but the team works out pretty well.

Yeah chainstunning won't happen, but you've got foul grasp on UB + the slowdown from ooze.  Sedna or Oak can still interrupt, so an enemy escaping is unlikely.

Ditto here.  Erebus is like a short range, high damage snipe.  Great for an unexpected 2v1 gank.

I've actually found one of the most confounding strategies with Erebus, is to grab the teleport favor item, and ALWAYS sneak into 1v1 situations and make them 2v1.

Erebus is pretty much awesome all round, wouldn't be surprised to see his undead knees smacked with the nerfbat.  

Naw man he already got nerfed, his damage isnt outrageous anymore with bite or anything, at this point in time I think every demigod is pretty balanced imo.

CONCUR!  Nerfbat not required.

Erebus + UB. Once Erebus gets charm and UB gets foul grasp, they will kill any lone demigod without any chance of him escaping.

Actually, this is a huge problem I have with UB. Foul Grasp is kinda OP because it breaks a major mechanic: stun immune. You can charm/boulder roll somebody immediately after they have been FG'ed because FG doesn't count as a stun, though it clearly is. Oh well, I guess UB doesn't have any other team synergy if not for this, so whatever.

X+Y