User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-3146930-20130601104422

So now that I have had time to examine the cover, I guess it is time for

Percy and Annabeth
So lets look at the biggest part of this cover first. Now, has anyone noticed anything strange about the two in this image? For me, they aren't wearing their Camp Half-Blood t-shirts. Percy had it on in The Mark of Athena cover, but not this one. Annabeth doesn't have it on either. Now you could say that they changed clothes, but I don't think so. Their clothes seem to match, or at least be made from the same stuff. Look at the ribbon holding Annabeth's hair in place, as it looks like it might be the same material (possibly ripped from their shirts). It also looks like these weird looking shirts have a hood, so obviously these aren't their camp shirts. In fact, they kind of remind me of ponchos. Same could be said for their boots, which seem to be knee high. What does this have to do with anything? Nothing really, but maybe someone is helping them in the pit.

Next, Percy's face. As we can see his hair is a mess and he's looking over his shoulder. However, he looks scared, as if something were chasing the two of them. He is looking over his shoulder at whatever is chasing them, possibly Arachne as that white stuff at the bottom of the cover could be spider silk. There is also something on Annabeth's right leg that looks like...I have no idea. It kind of looks like roots or something holding onto Annabeth, which could be the reason Percy is holding her. It could also be that her ankle didn't heal, but when Piper broke hers, she was good after a day or two with some nectar.

The Doors of Death
The other big attention getter for this cover. The most obvious thing is that they're closed, but this is most likely just for artistic reasons, as you couldn't see the doors if they were open. But look at the doors for a minute, now look at this image...go on, I'll wait. Ok, back? Good. The Doors of Death look a lot like the design of the elevator for the Empire State Building...just something I thought I would point out.

As far as the doors themselves go, take a good look at it. The Doors of Death are standing at the top of a hill in clear view of anyone trying to find them. It is almost as if someone ( *cough* Gaea *cough* ) wants them to be found. Also look at the chains holding the Doors of Death. Some may say that the doors just look like that, but I disagree. Thanatos mentioned back in The Son of Neptune that the Doors of Death's "...location isn’t…well, it’s not entirely a physical place." This could mean that Thanatos is able to move the Doors of Death as he wishes. There is no reason for the Doors of Death to be in Tartarus, as not even the gods go down to the pit. The chains could mean that when Thanatos was captured, Gaea forced the Doors of Death into Tartarus and had them chained, preventing them from moving; much like how when a god is trapped they are powerless.

Background
Sort of what I expected Tartarus to look like. Lots of fire and brimstone. Some of the black rock (especially on the right) seem to have the faces of trapped souls on them, which is a nice touch. However, the fact that everything seems to be bent, as if everything is being pulled toward the center is a little offsetting. Also, Monsters. In the top right corner is a pair of flying monsters that sort of look like the Furies. I would say it is the Furies themselves, but it kind of looks like there might be four of these flying things so it can't be the Furies. They could just be creatures that live in Tartarus, like undead vultures that prey on weakened beings. There also seems to be rivers of lava around, so no water for Percy...or Annabeth...what are they drinking and eating?