I have to post this in regard to many people that consider ESO is going to throw the lore on the window by introducing new enemies and NPCs that aren't supposed in their headcanon to exist on this period in the first place, but I also want to mention a few lesser-known creatures present in the TES universe that may appear or not in the future expansions. The problem is that many of you beside ESO have played only Skyrim, maybe Oblivion and Morrowind too, but there aren't many aware of the other 8 games in the series, one of the most important being Arena and Daggerfall as they are the base for the entire lore, but still, I see many of pretending to be some sort of loremasters here, complaining about something that is plausible or logical to be lore breaking, while you, in fact, are those breaking the lore with your ill-informed arguments. I know this topic is more suitable for the Lore section of this forum, but on General is most likely to reach more people.
I'm going to start with the few Dragons are still alive during the 2E. A fact that many of you overlooked is that not all Dragons were slain during the Dragon War and in the absence of Alduin, some of them went into hiding waiting for their leader to return, or took their own path.
1. Paarthurnax. Really!? Do I have to mention him here? The one who betrayed Alduin and allied with the mortals during the Dragon War? How do you believe that he was still alive in 4E 201? Alduin reviving a traitor would make no sense. Instead, he chose to hide at the summit of the Throat of the World serving in secret as the master of the Greybeards as the Blades are trying to hunt him for his war crimes against mortals. Paarthurnax is alive during 2E 583.
2. Nafaalilargus. Is the first Dragon to ever appear in a TES game, more exactly in The Elder Scrolls Adventures: Redguard (1998) about which many people, unfortunately, have no idea about. He served as a soldier in Tiber Septim's army during his reign until was slain by Cyrus in 2E 864. As Cyrus wasn't a Dragonborn, Nafaalilargus wasn't really killed. Another Dragon called Nahfahlaar, which description is pretty similar to that of Nafaalilargus, was recorded by the Blades in their Atlas of Dragons, as being one of those Dragons that survived the Dragon War by allying himself to mortals and serving as a mercenary in the service of some important political figures, making his hunt impossible for the Blades. He was last sighted on 2E 369 after escaping the Blades. Nafaalilargus is alive during 2E 583.
3. Ahbiilok. Sightings dating back to the early years of the Dragonguard throughout the northern Jerralls. Multiple attempts to kill him have failed. He is believed to be lairing somewhere in Morrowind. This is a quote from Atlas of Dragons. Ahbiilok is possibly alive during 2E 583.
4. Mirmulnir. He's the first Dragon you fight in Skyrim, before that he was last sighted in 2E 212. It's unknown if he survived until Alduin's return, or he was slain and resurrected. Mirmulnir is possibly alive during 2E 583.
5. Vulthuryol. He's a Dragon that hides inside Blackreach. As the area is quite impossible to be accessed by something so big, most probably he was trapped there by the Dwemer and survived until the Last Dragonborn finds him. Vulthuryo's survival during 2E 583 is just an assumption.
Now enough about Dragons as I'm already tired to hear about their inexistence during the interregnum. I'll continue to mention some creatures about which both Bethesda and ZoS forgot.
1. Dragonlings. Did I say I'm done with the dragons? Not until I don't mention those creatures very similar with the dragons. Even that they are looking pretty much alike, they aren't related to the Dovah. However, they seem to hold some kind of intelligence since they have developed their own language. They appear in TES II: Daggerfal, but according to wiki, there are some mentions in Skyrim about them that I never encountered.
2. Centaurs. The same centaurs you know from the Greek mythology, half men, half horses. They appear in Daggerfall and I hope to see them again in a future DLC/Chapter or in a future TES game, maybe in TES VI.
3. Nymph. They are fairies which appearance is that of beautiful naked women. They are other creatures from Daggerfall that we may never see again in a future TES game as nudity is involved, but still, Lamias appeared as having the upper body of a naked woman and a long snake tail instead of legs, so with a bit of redesign to make them fit the ratings there is still hope to see them again.
4. Imga. Their absence is ESO feels like a waste of potential from ZoS side to include another race to inhabit Valenwood. They are an overlooked species of the beastfolk that I hope to see in a future game set in Valenwood.
5. Lycanthropes. The most known of them are the Werewolves that are present in Daggerfall, Morrowind, Skyrim and ESO, but there are other species like the Warebears (Daggerfal and Skyrim), Wereboars (Daggerfall), Werebats (there are big bats in ESO called werebats, but I find it quite silly from ZoS side as they deserve a bit more love than that), Werevultures, Werecrocodiles, Weresharks and Werelions. Some future content dedicated to them would be amazing.
Other stuff I'll like to explain a bit beside creatures, but I'll have to do it on short as it took me more to write this post than I expected as I had to consult some sources again.
Shadow magic. An obscure, yet very powerful school of magic not very exploited in the games. In ESO the Nighblades are those who can harness its power, but it's vastly explained in Shadowkey which is a game from the series so obscure as the magic itself.
The Parliament of Craters. Sentient being living on the moons, that they were nearly brought to extinction by Nerevar. The only source of information about them is Sermon 16 from 36 Lessons of Vivec. However, the existence of some moon people can be exploited for future content.
Airships. Constructed by the Dwemer, few of them are still intact and used by imperial agents and rich nobles. Redguard is the only game where you can see one that is still in function, however, in both Morrowind and Skyrim you can find a crashed airship on Solstein.
The possible existence of the gunpowder. In Redguard there are barrels that can explode in contact with fire, also during a cutscene you can hear cannons.
@GabiAlex -
PC EU MegaserverDelora Xiaphia - Aldmeri Dominion - Nightblade Bosmer
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Ophelia Adel Maris - Aldmeri Dominion - Sorcerer Breton
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Floriancen Larethian - Aldmeri Dominion - Warden Altmer
Zahir at Unar - Daggerfall Covenant - Nightblade Redguard