Statements made by Mankar Cameron:
How little you understand! You cannot stop Lord Dagon. The Principalities have sparkled as gems in the black reaches of Oblivion since the First Morning. Many are their names and the names of their masters: the Coldharbour of Meridia, Peryite's Quagmire, the ten Moonshadows of Mephala, and ... and Dawn's Beauty, the Princedom of Lorkhan... misnamed 'Tamriel' by deluded mortals.
Yes, you understand now. Tamriel is just one more Daedric realm of Oblivion, long since lost to its Prince when he was betrayed by those that served him. Lord Dagon cannot invade Tamriel, his birthright! He comes to liberate the Occupied Lands!
Ask yourself! How is it that mighty gods die, yet the Daedra stand incorruptible? How is it that the Daedra forthrightly proclaim themselves to man, while the gods cower behind statues and the faithless words of traitor-priests? It is simple... they are not gods at all. The truth has been in front of you since you first were born: the Daedra are the true gods of this universe. Julianos, Dibella and Stendarr are all Lorkhan's betrayers, posing as divinities in a principality that has lost it's guiding light. What are Scholarship, Love and Mercy when compared to Fate, Night and Destruction? The gods you worship are trifling shadows of First Causes. They have tricked you for Ages.
Why do you think your world has always been contested ground, the arena of powers and immortals? It is Tamriel, the realm of Change, brother to Madness, sister to Deceit. Your false gods could not entirely rewrite history. Thus you remember tales of Lorkhan, vilified, a dead trickster, whose heart came to Tamriel. But if a god can die, how does his heart survive? He is daedroth! TAMRIEL AE DAEDROTH! "This Heart is the heart of the world, for one was made to satisfy the other." You all remember this. It is in every legend. Daedra cannot die, so your so-called gods cannot erase him from your minds completely.
I'll add whatever evidence is stated to this list.
Current Evidence Linking Tamriel to Oblivion:
1. A very materialistic fact, Daedra Hearts and Skin have the same alchemical properties as Human Hearts and Skin.
2. Tamriel can be linked to the other realms of Oblivion via gateways. There are apparently magical barriers to stop this, But Peryite's Shrine Quest proves how Peryite can open a portal to his realm of Oblivion and there is also The Strange Door to The Shivering Isles which remains open forever.
3. Despite being in different realms, Daedric Princes can communicate to you via their shrines.
4. Mehrunes Dagon was able to materialise himself in Tamriel.
5. There are many Daedric relics which can materialise in Tamriel through the will of the Daedric Princes.
6. Mankar Cameron states that Tamriel is actually called Dawns Beauty and was lost to its prince, Lorkhan. Looking at all the other realms of Oblivion, Dawns Beauty does seem to make a complete set of realms.