Hades is always allowed in Olympus, he just chooses not to go there because he feels he doesn't fit in. He makes the other Gods uncomfortable and nervous.
Hades was not banished from Olympus.
Poseidon had a palace on Olympus, but Hades did not.
Hades, The god of the Underworld. He was never allowed to enter Olympus except when invited by Zeus for important matters.
Because Hades does not reside on Olympus as the other Gods do, Hades dwells in the Underworld.
Because if he hadn't,then Hades would have made Olympus a total wreck!
He is not Olympian, Hades dwells in the Underworld by preference rather then the lofty heights of Olympus.
Hades never was technically banished. But he wanted to be super powerful so he moved to his realm, the Underworld, where theoretically he doesn't need to listen to Zeus. That is wrong. Hades never wanted to be in the Underworld. In fact, he is bitter sometimes because he is stuck in there. He is allowed on Mount Olympus, but he can't live there. His realm is the Underworld.
The Blood of Olympus.(it said that in the back of"The House of Hades"
Because Percy has already gone to Hades' palace and it is the same as Zeus' but darker and he realises that its like that because Hades is always left out and according to the start of the first book: Percy Jackson and the lightning thief, Hades is only allowed to visit Mount Olympus twice a year.
There wasn't anything stopping him, it's just that his realm was the underworld, that's where he ruled over.
Hades does not have a throne in Olympus. His throne was in the underworld.
Hades had his own realm of which he was King, that of the Underworld, and Hades did not often leave it.