Well, after having some fairly good success with my Erebus in custom matches(I havn't played pantheon yet, never had a good chunk of time to commit to yet), I've decided to write down my method for all to see. Not like it was a big secret anyway.
The idea behind this Erebus build is to combine his abilities as an assassin and his strengths as a general into a build that can maximize damage output and take out enemy demigods with fairly little trouble at middle to higher levels. Strengths of the build include high damage output, and long lastability against towers thanks to minions. Weaknesses include Erebus' inherent weakness against citadel breaking, and no way to stall matches, with a high reliance on bat swarm as an escape tool. Also, the lack of a powerful/reliable AoE hurts the build against giants, another Inherent weakness of Erebus. In the end, the basic philosophy of this build is to maximize what Erebus is good at (being a versatile split between assassin and general), while trying to avoid his weaknesses, rather then fixing them.
OVERHAUL UPDATE: The build still mixes his assassin and general abilities, but focuses more on general style gameplay early on, getting nightcrawlers to swarm in like locusts. It provides a massive boost to his damage abilities, and is a great way to get a very intimidating army that will slow enemies down at the least, and rip them to pieces at the very best.
Level 1: Bite(1)
Level 2: Coven(1)
Level 3: Improved Conversion Aura(1)
Level 4: Bite(2)
Level 5: Bat Swarm(1) or Coven(2) (use your judgement)
Level 6: Bat Swarm(1) or Coven(2)
Level 7: Bite(3)
Level 8: Coven(3)
Level 9: Nothing
Level 10: Bite(4) and Bat Swarm(2)
Level 11: Improved Conversion Aura(2)
Level 12: Improved Conversion Aura(3)
Feel free to throw Mist or Poisoned Blood in there if you think you need it. Level 13 and on is basicly whatever you feel you need, as the basic build is pretty much complete at this point. If you've been doing everything right, the game shouldn't have much more time left in it anyway.
Skill summary and reasoning:
The idea behind this build is to grow up an army of Night Walkers as fast as possible in order to crush enemies before they know what hit them. The raw firepower of the Night Walkers, the Idols, and Erebus himself early on is enough to send most demigods packing.
Skill description and usage:
Bite: Erebus' signature move. Does decent damage, regains health, and debuffs. Use this skill to open a match, and use it to end a match. The basic rule is just to use it. Early game, the armour reduction from this move can cause your opponent to have negative armour, which means the damage they take will skyrocket. This can lead to some real early game dominance against enemies that don't buy armour. Note: With the new Bite Nerf, it'll be harder to kill people with this move. It'll be less spammable, and do less damage and armour reduction. It's still going to be your integral move, but you probably won't be killing as much with it. That's fine though. Remember, your job is to keep flag control. If they run, it's just the same as them dying, so long as you get that flag.
Mist Form: Not a fan of this skill. It's a great stall move or evasion move, but not much else. Use it if you need to get some pressure off of you, I guess. But then again, it might just be better to run away with Bat Swarm. If you're against Rook or Regulus, you can use it to quickly evade their hammer slam and snipe attacks, as well as remove debuffs, such as UB's venom spit. One poor move that I notice many Erebus players make is that they use Mist when they're low on health, and then just wait until their mana runs out or their opponent moves on(this is a different story with Snipe support, but in most cases, that isn't happening). Thing is, that's not what usually happens. Most smart players will simply walk out of the mist, wait for you to reform, and then kill you now that you're not only low on HP, but have no mana to help you either. It should be doubly noted that Mist Form IS NOT AN ESCAPE MOVE, it is only an evasion and a stall move. Any other use of it will hurt you quite a bit.
Mass Charm: Very versatile move. Use it to halt the offenses of a powerful enemy, use it to buy time for bite to recharge, use it to keep an enemy in place so your allies and minions can beat on him, use it to stop an enemy from running away, use it to stun enemies for a quick getaway, the list of uses goes on and on. However, it's a poor interupt, due to the long cast time, and the high mana cost can end up hurting you if you use it carelessly. Despite it's many varied uses, make sure you have a purpose in mind before you use it, as it's not something you want to waste. Muddle also makes it able to slow down the recovery of skills for your enemy, making them even weaker against you. At higher levels, once you have access to muddle, it can be quite useful late game, but in terms of stuns, it's a fairly weak move, thanks to it's long cast time. Early on, the stun's too low to be of much use.
Bat Swarm: A chaser, an approach, and a running move. Against people running, if you know you can kill them without being killed by towers(this is important), just warp in, get the last hit, and you've got your kill. If you're fighting ranged attackers, just use this to get right in their face without taking too much damage. If you're taking hits, and need to get away fast, you know the drill. It also makes a decent AoE for killing creeps. However, there are a few things to keep in mind with this move. Namely, it has a long recovery, and high mana cost. If you use this move, you need to commit to whatever action you intended to do in the first place. Especially early game, where the mana cost could end up leaving you with little else to do. Second, you need to be very careful with how you chase or approach with it. If you chase someone with it, and their buddy comes to rip you a new one, there's not much you can do, since it's already been used up, not to mention that your mana stocks probably got a lot lower. Essentially, abuse this move, but be very careful when you do it.
Poisoned Blood: Buy it for the health regen. Nuff' said.
A note on Vampiric Aura: Not sure if it's really worth buying, as I've never really noticed its effects being too integral to victory. Might be worth passing up. Maybe once I get some more numbers on this skill, I might be able to get a better opinion of it.
Improved Conversion Aura: The first level of this skill is awesome, as it doubles your chances of getting a nightwalker. Not to mention the health boost it gives them. After that, it's not as effective as some of your other skill options, but is still worth getting mid-late game, in order to keep your minions viable as the game draws on.
Coven: Freaking awesome passive. 12 Night Walkers is nothing to scoff at, and the damage increase is also pretty good too. Invest in this early, and you'll be a force to be reckoned with.
Favour: I hate favour, I never have any. Swift Anklet or Blood of the Fallen. Lately, I've been leaning more towards Blood of the Fallen, as the health boost is incredible. Erebus is also pretty fast as it is, and once he gets bats, gets even faster, reducing the need for a speed upgrade. However, the Swift Anklet is still very notable, simply because it helps you zip around the map and capture flags more, which is something a good Erebus wants to do very often. Really, it's up to you.
Throughout the game: Teleport Scrolls and Flag Locks are always great items to have on hand. Always try to keep a few on hand, should the situation where they're needed arise.
Early Game: Level 2 Archers. Early on, I find Erebus' best tactic for survival is to kill the enemy before they kill him. Archers give him the extra punch he needs to do that. Also know that you don't really need to get the archers. They're useful, but if you think you're better off saving your money for later items, that's fine. Or, you could buy other equipment instead. You need to evaluate your situation and what you have available to you, really.
Early-Mid Game: Level 4 of each idol, Vlemish Faceguards. Get the idols and faceguard in any order you want. Personally, I get archers>priests>Vlemish Faceguard feel free to skip minotaurs, they're really not that good. Don't worry if you have to buy lower level minions as you go to keep up with the competition, you get 80% of your gold back when you sell the idols, so upgrading is fairly painless. Also, if you do buy lower level minions, make sure you have a summoned set before you sell. That way, they stay, and you get your upgraded idol. So long as those low level minions don't die, you get some extra firepower. It's temporary, but it's a nice little upgrade to have. Anyway, with that, you have your integral equipment. From there on out, save for the citadel, and buy lots of HP equipment. Unbreakable Boots, Hauberk of Life, and Scale Male is the usual order I buy in. They make you a very powerful wall with lots of HP to soak up damage. Hauberk also makes your minions more resiliant. Remember though, if it means buying giants and making the final push sooner, try to buy cit upgrades first.
Mid Game: As soon as your integral equipment is complete, start worrying more about citadel upgrades. Don't put all your money into citadel, as you may still need equipment to stay on the same level as other DGs, despite your fast mid-game growth. Just remember to always keep some money saved away for those upgrades. Also, it's a good idea to keep in mind how much money you and your team will need to save for giants. This is especially important since, as Erebus, your structure breaking abilities aren't exactly that good(although for some reason, I always get the Structures killed favour bonus...). For that purpose, you'll need giants to break stuff for you.
Mid-late game and late game: Citadel upgrades, and whatever other things you feel a yearning for. My games rarely last long enough for artifacts to come into play, so I can't really give any advice about that. Really though, once you get to the point where everyone starts getting artifacts, I get the feeling that the game has gone on longer then it should have, and you're doing something wrong.
Other items that may be useful to you include:
-Gloves of Fel-Darkur
Minotaurs: Really... not that good. Weak attacks, and no range means they'll usually just walk up to something and die. On the good side, they're very durable for a minion. On the worse side, Nightwalkers usually do that job fairly well, and don't cost you any gold. Don't buy them unless you feel that you need even MORE minions. They're not worth the gold that goes into them.
Archers: Freaking awesome. Decent damage, and great range. They can shoot outside the range of towers, so if you're feeling tactical like, you can just park them in front of a block of towers, and just have them slowly pick the buildings off while you go do something else. Of course, don't expect them to do too well left unattended, their survivability can be attributed to their range, where they can usually sit at the back of your ranks with very little chance of actually being attacked. Once someone actually starts to hit them, they crumble like paper.
Priests: Another freaking awesome minion. They do a little bit more damage then archers, although they have shorter range(enough to die in combat, although they still can keep themselves safe from melee combat). They're also a little more durable. However, the best perk is that they heal you. The higher the level, the more they heal. Each priest heals every 10 seconds for between 10% and 15% of your max health... or something like that. Point is, they're freaking awesome, and to ignore them would be a horrible waste.
Nightwalkers: Individually, they're horrible. Low life, low damage, slow attacks, terrible AI, and they tend to have trouble attacking enemies that actually move. The good part? You can get 12 of them. Now, you may be thinking "Shit is shit, no matter how much," but when you think about it, dumping a whole truckload of it on top of your opponent's head is pretty freaking effective. So, a Nightwalker may look like, and probably is, a rolling piece of turd, but when you have 12 of those ripping at something, chances are it's going to start crying.
First thing to note: Flag control is VITAL for Erebus. He lacks the firepower to effectly take down citadels and other structures quickly, and his squishiness makes him an easy target when he tries, and as such, works best by relying on giants to get this done. For that reason, flags are the most important target for you to watch for, above other demigods, above creeps, and above towers. If a flag is taken by an enemy, make sure you take it back as soon as you possibly can. Flag locks can be essential because of this.
Your job with this build is essentially offensive support. It's up to you to keep flags cap'd, your enemy scared, and later on, your portals allowing the main offensive through. For the most part, you shouldn't even be within sight range of the enemy citadel. That's not your job. Your job is to make it so that the citadel killers have an easier time doing theirs.
Early game, you're very fragile. Stay away from guys like UB. Instead, creeps give great experience, so make sure you get those when you can. However, gold can be hard to come by early game, and for that reason, it may be worth your while to take out a few demigods. Your main targets at low levels should be squishies like Rook and TB, and, should your opponent somehow let you get close enough, Regulus(in fact, in any game where Erebus is on the opposing team, Erebus players are legally required to kill him at least once, and it is encouraged that they continue to harass them for the rest of the game. Those annoying fuckers need to be put in their place ). With the new Bite nerf, Erebus won't beat Sedna, but should be able to survive against her. Chances are that the match will end with one or both of you running, but you'll never get the kill. QoT shouldn't be too hard to kill, but a good QoT probably won't let you get to her by this point in the game. Oak is a fairly even matchup early on, and I like to think throughout the game, but be weary of his powerful support skills. Don't try to take on enemy Demigods 1 on 1 until you're around level 4, when bite gets a big enough damage buff to be fairly powerful at that stage, enough to be a killing move. Otherwise, only go for demigods at lower health. Until then, just try to damage them until they run off.
Mid game, you become very, very powerful. Short of Regulus(if you see him, he's doing something wrong), you should be able to take down any other Demigod in 1 on 1, although that's not to say that your matches won't be close. If Rook has gotten up to speed by this point, he can be a tough fight. In that situation, it may be better to let ranged attackers kill him. Sedna will always be a close match, and will almost always end with both of you running away, unless you get some help. UPDATE: With the new update, Erebus shouldn't even hope to actually kill Sedna. Any Sedna who manages to die against an Erebus should never even consider playing Demigod again. With all your minions in tow, UB should go down before you, but don't expect to get away from it without any scars. Also, if a UB health stacks, and you don't, it won't be pretty for you. Against UB, you need the equipment to match. Torch Bearer will run into trouble against you alone, and is a fairly easy kill so long as you don't mess up. Just don't expect too many of your minions to survive the fight against him. Essentially, you'll be fine so long as you keep the flags under control. Remember, flags first, kills second.
Late game, the shit hits the fan. If enemy giants are on the lose, your only real option is to cap the enemy portals. Erebus lacks the tools to take masses of giants on head on. If this ends up happening, portal flags take precedence over any other objective on the map, other then your citadel. Also, your enemies have probably caught up in their skills by now, so the advantage you had at level 10-15 is now gone. This makes it even harder for you. Late game is not something you want to be experiencing with this build.
Conquest: This guide was written with Conquest in mind. No changes to playstyle have to be made to accomodate this mode.
Dominate: Dominate is pretty much Conquest with a different name. No changes here.
Slaughter: This is where things get a bit different. Don't worry about citadel upgrades, most of your gold should be going into minions and equipment. Capture flags when you can, the effects will really help, and kill when you get the chance. Don't take too many risks, remember, a death here helps your enemies a lot more then it does in any other mode. If you can dominate the creep lanes and keep your enemy from getting them, you'll have a much easier time.
Fortress: It's like Conquest, but with 3 targets. Let giants do the work.
Weaknesses of Erebus/how to counter this build:
-any way to mitigate the damage from bite. Erebus only regains health if he does the damage. Correction: Erebus still heals from the bite, but skills like Oak's sheild should still ignore the debuffs and damage, making it still a good counter.
-because of his squishy nature, stuns will rape Erebus.
-Quite a bit of gold ends up going into Erebus' minions for this build. Chances are he can't afford much equipment early on because of that. AoE'ing his minions away makes this build much weaker then it is with the minions. Erebus' DPS and survivability will take a huge blow should this happen.
-Erebus' skills are integral to his survival. As such, mana denial and silence will break him.
-Despite his mobility, Erebus' Bat Swarm has a long delay and high mana cost. Catching him after using this move almost always means certain death.
-Erebus isn't really very good at breaking citadels. If you can stop him from getting giants, he'll have a much harder time actually winning.
-With the new update, Erebus should never, ever kill Sedna alone. Any Sedna who dies against an Erebus should never touch this game again
I hope you found this guide helpful, whether you play as or against Erebus, and if anyone can help me improve this build or this guide, I'd be happy to know.