"Behold! The Citadel of the Deathlands, standing tall and wide. Guarded by millions. Ruled, by one..."
~Eristor, when returning to his homeland. Edit
The Deathlands were located East of Mordor, in the Eastern Desolation. The Deathland Elves, also known as Death Elves, also known as the Morangdi, were a quiet and corrupted folk. The Citadel of the Morangdi was located in the center of the Deathlands, guarded by millions of soldiers.
The history of this wicked place starts since the beginning of orcs. After the fall of Gondolin, it's enemy, Maeglin survived. Running away, trying to find somewhere to hide from Morgoth and the Elves all together, he ran so far, that he reached what we now call the Deathlands in 21 days (at that time Arda was much wider). Panting, he saw the magnificence of this place. For many long years, after Morgoth was trapped in the void, and the Rise of Sauron, Maeglin sat, and wondered, what life would be like if he didn't betray Gondolin. Time and more time passed, until Maeglin no longer wondered about things, he did them. When he wondered he would build this place into civilization, he did. When he wanted company, he had company. When he wanted to corrupt Elves, he did! Magellan founded the Deathlands, corrupted the Elves that dared to pass in his territory (which was a reasonable amount, at that time the Elves had a good trade with the East), built the citadel of the Deathlands, and founded the Kingdom of the Morangdi. This Kingdom lost it's first King swiftly. Maeglin ran away again due to a war with surrounding tribals who invaded the Citadel. He never stepped foot in the Deathlands again. Many more kings came and went, but the most famous of the Deathland royals was Cross. Cross was a Deathlands prince who had a thirst for adventure, and with three friends, departed to locate the Lost Gate of Abaddon. Cross finally found the Gate, and was corrupted by Abaddon. He served the Overlord for a hundred years until he was purified by a band of men and elves seeking the Gate.
The Deathlands was exactly like the rest of Mordor, other than that no Olog Hai, orcs and wargs lived there. It was a plain, and some fertile land, near the rivers. It was no more unique than Mordor in any other way.
The most notable members were Maeglin, Cross and Eristor. Senator Grôion is known for trying to bribe the Noldor with sticks and Mordor "flowers". He died a horrible death.