Boethia

Boethia's shrine is waaay up in the Valus Mountains, on the eastern edge of Cyrodiil, near the border with Morrowind. If you examine your map and find the text "The Valus Mountains", you can find the shrine a bit to the west of the "m" in "Mountains". It's difficult to reach, however; you'll probably have to scout around for Fort Facian, which is located to the southwest of the shrine, and follow the rough path there up to the shrine. You'll need to be level 20 before you begin this quest, so don't make the trip unless you're going to be able to attempt it.

Boethia's offering is a Daedra heart, easy enough to find in any Oblivion plane. When offered, he'll tell you of your task: enter a special plane of Oblivion and take part in the Tournament of Ten Bloods. When you pass through the portal, you can't come back until you win, so be sure to bring along anything you need. Special equipment, potions and poisons, filled soul gems, repair hammers, etc.

The Tournament When you enter the portal, you're given a moment to collect yourself, then are told that the Tournament of Ten Bloods will begin when you enter the gate on your right. And indeed it does! The goal here is to kill nine enemies, one of each different race, each of which has boss-level stats and armor. (Whichever race you chose as your own will not be represented, so you won't have to practice any fratricide, thankfully.)

You'll have to have a bit of longevity if you want to survive Boethia's challenges.

The Orc and the Redguard here are likely going to be two of the more difficult enemies you'll face, and unfortunately they're both at the very start of the tournament. Both have magical weapons that will add quite a bit of damage to their attacks, and both have a large amount of health to draw on. These two will be perfect targets for any high-level poisons that you have, although the Redguard will likely have a small amount of resistance to poison. Stay away as best you can to prevent them from whacking you while your poison works its magic, then finish them off with whatever you have at your disposal, perhaps using scrolls if you happen to be a melee warrior. (The Nord character is likely another strong fighter, but as our character was a Nord, we can't speak from experience on this.)

Personal playstyles aside, the rest of the enemies shouldn't be quite as powerful as the melee warriors. The archers are especially useful to kill, since you'll be able to look some incredibly powerful arrows off of their bodies; get up close as soon as possible to prevent them from using them on you! Most of the characters will have plenty of great loot to carry, so be sure to bring some potions of Feather to help you carry it all out of the plane. Don't forget that you can rest for an hour between fights to restore your health, and don't forget to use the weapons that you like against subsequent opponents to prevent you from having to constantly recharge your own. One of them seems to always drop a Greater Staff of Lightning, which will make for some quick fights against the rest of the enemies.

Be sure to grab anything from the corpses that catches your eye, as you won't be able to return to this plane after you leave. When you do return and speak to Boethia's shrine again, he'll reward you with Goldbrand, a decent enough sword with a 22 point fire damage bonus. You've probably been able to make better ones with Sigil Stones, but whatever; we're not going to tell him what to give us. To be fair, it is an exceedingly quick sword for the damage it does.

Clavicus Vile

Clavicus Vile has one of the shorter quests in the game, albeit one of the more interesting. You can find his shrine just to the southwest of the Imperial City. If you leave via the west exit and take the roads south from the Wawnet Inn, you'll eventually run across Fort Virtue. Head into the woods to the southwest of the fort and you'll shortly stumble across Clavicus Vile's shrine. You'll need 500 gold to activate the shrine, and will have to be level 20 to start the quest here.

When you do so, Clavicus will tell you of a sword embued with the soul of a warrior named Umbra. The sword (also called Umbra) is desired by Clavicus, and he wishes you to track it down and return it to him. He'll tell you to begin your quest in Pell's Gate, a village near the shrine. You'll have to speak to a character named Irroke the Wilde who, when he feels comfortable with you (at a high Disposition, in other words) will tell you of an apprentice of his who found the sword and was possessed by the soul inside. She's to be found in Vindasel, an Ayleid Ruin just to the east of the Shrine of Clavicus Vile, near one of the bridges over the water.

Killing Umbra is a difficult matter, but by level 20 you should have the tools to take her down.

Killing Umbra Now, unlike many quests of this sort, there's no way to get the sword from Umbra (as she's calling herself) without killing her. And she's hard. Quite hard. Luckily for you, if you're attempting this quest at level 20, you should have the tools required to take her on: a weapon with a 25-point magical damage enchantment, a hearty shield, plenty of health, and potions with which to heal yourself during the fight. Stealth characters will want to rely on the most powerful damage poisons you can create and attempt to evade her powerful attacks. Mages should rely on any kind of powerful staves that you might've found, or high-damage spell attacks. Any way you go, you might want to try completing Boethia's shrine quest and loot the equipment from the characters found within to give you an edge over Umbra.

Luckily, there is a little trick to taking her down without getting into range of her attacks. If you look around in her little room, you'll notice that there's a pillar that's been broken off. If you jump from the table to the pillar's midsection, you should be able to get yourself well off the ground and out of range of her attacks. This will require either a large skill number in Acrobatics, the Boots of Springheel Jak, or, if you're willing to get up there the ghetto way, you can upend the little wicker basket by the table, place it upright on top of the table, and use it as a springboard to get onto the pillar. From there, she won't be able to hit you, allowing you to fill her with arrows or spells as you like.

Alternately, you can try buying an item that'll help you take her down, like the Apotheosis staff from Rindir's Staffs in the Market District. Regardless, kill her and get the sword, which sports a permanent Soul Trap enchantment when you hit an enemy. Definitely worth using for a while, but if you're level 20, then you can likely find a Sigil Stone with the same effect, albeit without quite as lengthy a duration (120 seconds for the Umbra).

Handing It In Now, at this point, you can either return the sword to Clavicus, or just use it yourself for a while. It's worth having if you like powerful swords, if only because the Soul Trap enchantment eliminates the need for you to cast that yourself each time you want to capture a soul. The reward you get for giving up the Umbra to Clavicus Vile is a heavy armor headpiece that adds 20 points to your Personality, which isn't really worth trading in the sword for. You will need to complete this quest to attempt the quest for Hermaeus Mora, but you may be able to "complete" it by returning to the shrine and refusing to hand over the sword, which will let you retain it while still moving on to the Hermaeus Mora quest. Worth a shot, but save your game first, because the Hermaeus Mora quest will net you quite a nice reward; it'd be a shame to miss out on it.