dtgreene: (Assuming you're talking about Skyrim, as this mechanic doesn't exist in the rest of the series.)

First of all, reaching level 81 is not a requirement to make a skill legendary; it can be done before then, and the Ebony Warrior speedrun does just that. (More on that particular speedrun category later.)

When you make a skill legendary, it goes down from 100 to 15, *but* you still keep the level XP you gained from leveling the skill. Now that the skill is down to 15, you can level it up again, and gain more level XP, which in turn makes it possible to reach higher levels than you could otherwise. In particular, this allows you to level up past level 81, and keep leveling until integer overflow occurs.

This is also good for gaining extra perks. Not only are you refunded the perks you spent on the skill's perk tree, but those extra levels will earn you more perks. In theory, it is possible to acquire every standard perk this way. (A standard perk is any perk that can be gained by spending a perk point gained through leveling.)

As for that Ebony Warrior speedrun I mentioned? The idea is to kill the Ebony Warrior as fast as possible, but the Ebony Warrior won't appear until you're level 80. So, you need to level up really quickly in order to accomplish this task. Turns out that, once you get the Fortify Restoration trick going, you can level up your Alchemy from 15 to 100 by making a single potion. But that's only one skill, so by itself it will only take you so far. However, if you make it legendary, you can reset it to 15, then level it up to 100 with a single potion, make it legendary again, quickly raise it to 100 again, and repeat, gaining level XP each time. Repeat this, and you'll quickly level up, making it possible to reach the required level 80 fast enough for it to feel like a speedrun. (I seem to remember the time for this category being less than 15 minutes.)

trusteft: I read that when you reach level 81 you can make a skill tree Legendary which resets all the points you put into it and drop the skill down to level 15.

What's the point of this? Isn't that bad? I don't get it. Can someone please explain?

TAGma: You lose all perks, you will have to level up the skill to unlock them again.

Let's say you are a pure warrior build (heavy armor + two handed) + you hate magicka & stealth:
Without the legendary system, you need to level up all skills to 100 (alchemy, alteration, conjuration...) if you want to beat Ebony Warrior (he spawns at level 80).

By resetting the skills using the legendary system, this is no longer a problem, after reaching level 100 in Heavy armor, you can reset it (keeping the character level) - consequently you can reach player level 80+ with only 2 skills ( heavy armor + two armor) without any investment in magic/stealth skills.

Legendary system will also allow the player to unlock all perks in a single playthrough (player level 252).

trusteft: I don't know what this Ebony Warrior is exactly (no spoilers), but are you saying this enemy cannot be beaten unless all your skills are at 100? Is this a game design where if you say are a non magic user, or you are a magic user alone, can't beat this warrior? That sounds seriously flawed design.

dtgreene: No, you can kill this Ebony Warrior with lower skills; the problem is getting this Ebony Warrior to spawn in the first place. If you don't level up all your skills, and you don't make any skills Legendary, you won't even get to meet the Ebony Warrior in the first place.

I'm pretty sure that the intent of the developers is that, after doing basically everything else in the game, including all the guild side quests, as well as all the main and expansion quests, and exploring basically everything, fighting the Ebony Warrior would be the last thing you do. There's no other quest that requires that the Ebony Warrior be killed, and if you're at this point, it's going to be time to start a new character (or a new game, as you might very well be tired of Skyrim at this point), as there's nothing more to do with your current character. In other words, this encounter is meant as the final task a completionist does before putting the game away.

If you've been playing as a non-magic user or a magic user alone, and are not making skills Legendary, you are not going to see the Ebony Warrior, but that's OK, unless you *really* want to see this.

As for beating the Ebony Warrior, you don't actually need all those skills; some skills may not be that useful at such a high level (like Destruction, though it can be useful for boosting the power of certain enchantments), and some exploits exist (like the Fortify Restoration exploit) that may allow killing the Ebony Warrior without maxing out that many skills, or if you were theoretically able to encounter them at a lower level.

Someone could play the game for years and not even know that the Ebony Warrior exists.