Erebus has the ability to chase far past Reg's towers, so if Reg gets hit once or twice before running, he is screwed, EB gets a little damaged, bites, and batswarms to safety after the kill.
Or, EB fires off his HoB/RoM, and his minions chase Reg down.
small problem, once you kill him you'll still have 1 or 2 towers hitting you, his team also has the possibility to teleport in and kill you
but yes, I agree, this build is definetly killable, even 1v1, if you have enough speed / slow yourself, wich ereb obviously has
it's just annoying! got it, ANNOYING, not overpowered, not unkillable, not good, not bad, just ANNOYING!!
I think part of the problem is that you claim it is "The Most Annoying Build Ever" when clearly it isn't. By giving it such a title you invite severe critisism. Calling it An Annoying Build would have been more appropriate.
this is pure criticism, you don't have a single argument why this isn't the most annoying build ever or what actually is the most annoying build ever
this ist he most annoying build I have ever played in nearly 200 games ...
so in my opinion it is the most annoying build