Tamriel is filled with a host of nasty and powerful monsters, deadra, undead and the like; so much so that it is known as "the Arena". What is the toughest enemy you've fought throughout the Elder Scrolls series? Bosses and unique enemies are out; this is just about the infinitely spawning general enemies from the games.

I put the Goblin Warlord as number 1. They're fast, making it hard to keep up a ranged fight with arrows or spells, and they hit hard: staggering your character into dust. They also have what seems like unlimited health, making it so their battles often go on for a tediously long time even if you are strong enough the take them. As a bonus, they often come paired with a horde of lesser goblins or a shaman for support.

I would have gone for Daggerfall's Ancient Lich, which will instakill you without magical protection, but at least their fights are quick: you just need to save right before you fight them and then keep charging them until they miss you or hit themselves.