Oblivion:100% Completion

There is no message or alert that lets you know that you have completed everything the game has to offer. So, here is a list of all completable statistics within Oblivion; it is up to you whether or not you want your character(s) to achieve these ultimate measures of completion.

Summary of 100% Completion
Accomplishments
Quests Completed: 199 (or 208 if you fail Thieves Guild quests)
Master Skills: 21
Oblivion Gates Shut: 60
Horses Owned: 7
Houses Owned: 8
Stores Invested In: 94
Artifacts Found: 15
Skill Books Read: 109
Places Found: 367 (369 with the Unofficial Oblivion Patch)
Fame:  

Requirements not recorded in your Accomplishments
Grand Champion of the Arena
Attain all 7 Heaven Stone Greater Powers
Complete the Pilgrimage of the Nine Divines and be granted the '''''Pilgrim's Grace''''' Greater Power
Defeat Unique Enemies

Greater than 100% Completion Accomplishments
Nirnroots Found: 306 (309 with every official download installed)
Welkynd Stones Collected: 696-712* (minimum of 721 with Knights of the Nine, which also adds random chance stones)
Varla Stones Collected: 56-71* (minimum of 61 with every download installed)
15 stones appear in Vahtacen, all of which have a chance of being Welkynd or Varla stones
Collect all 366 Keys (or 374 with every download installed)
Collect all 109 Skill Books and 147 other Books

Completion Notes
Quests
There are 204 journal quests that can appear in the journal. At most, a maximum of 203 quests can appear in the journal, 199 of which can be completed. Additionally, there are seven quests that can be completed that do not appear in the journal.

If attempting to obtain the maximum number of quests, Eternal Exile is the one quest which mustn't be started (added to the journal) since doing so will mean expulsion from the Dark Brotherhood, which makes the remainder of the quest line inaccessible. Thus, 203 quests are the most that can appear in the journal instead of all 204.

If attempting to complete the maximum number of quests, there are four quests which can be started but cannot completed:
Two quests that can never be completed are Whispers of Death and The Arena. These are the final quests in the Dark Brotherhood and The Arena quest lines, respectively, and can be "completed" repeatedly for a gold reward, so they will never appear as completed in the quest journal.
Additionally, another quest that can be "completed" repeatedly is Cast out of the Thieves Guild. Since you are never permanently expelled from the Thieves Guild, you may always "buy" your way back in. This quest will also never appear as completed in the quest journal.
Expelled from the Fighters Guild can be started but must not be completed since doing so will permanently expel you from the Fighters Guild and render the remainder of its respective quest line inaccessible. Additionally, it is impossible to be permanently expelled after you have become Master of the Fighters Guild.

Thus, of the 203 quests which can appear in the journal, 199 quests are the most that can be completed.

Several quests can be rendered inaccessible or unable to be completed because of conflicts with other quests. It is therefore advised to plan when you time your quests to start or finish.

Main Quest Line - 20 Quests
There are 17 main quests in this quest line with three side quests, two of which can be missed, one of which does not appear in your journal:
Attack on Fort Sutch (which does not appear in your journal) begins with the completion of Dagon Shrine and becomes inaccessible with the start of Light the Dragonfires.
Allies for Bruma begins with the completion of Bruma Gate and becomes inaccessible with the start of Defense of Bruma.

Dark Brotherhood - 34 Quests
There are also a few possible missable quests in the Dark Brotherhood quest line:
The Renegade Shadowscale must be completed before The Purification, otherwise, with the death of Teinaava, this quest cannot be finished.
Darkness Eternal must be completed before The Purification, otherwise, with the death of Vicente Valtieri, this quest cannot be finished. Additionally, one must also not be a Vampire or this quest will not be made available to start.
A Dark Exile and Another Dark Exile must be completed before the completion of The Purification. Subsequent to this, it is impossible to break one of the five tenets.

If going for the maximum number of quests, Eternal Exile is the one quest which cannot be started (added to the journal) since doing so will mean expulsion from the Dark Brotherhood, where the remainder of the quest line is then inaccessible.

If going for the maximum number of completed quests, Whispers of Death can be started but not completed. It is the final quest in the Dark Brotherhood quest line, and can be "completed" repeatedly for a gold reward, so it never appears completed in the quest journal.

Fighters Guild - 20 Quests
If going for the maximum number of completed quests, Expelled from the Fighters Guild can be started but must not be completed since doing so will disable completion of the quest line. Additionally, it is impossible to be expelled after you have become Master of the Fighters Guild.

Mages Guild - 22 Quests

Thieves Guild - 14 Quests
If going for the maximum number of completed quests, Cast out of the Thieves Guild can be started but not completed. It will never be removed from your journal despite completing it and can be repeatedly completed. This brings the maximum up to 208, but requires you to fail nine of the Thieves Guild quests (May the Best Thief Win, The Elven Maiden, Ahdarji's Heirloom, Misdirection, Lost Histories, Taking Care of Lex, Turning a Blind Eye, Arrow of Extrication, and Boots of Springheel Jak).

Main Cities - 44 Quests













































Villages and Inns - 11 Quests












Arena - 1 Quest
The Arena:  

Daedric - 15 Quests


Master Training - 21 Quests


Non Journal









Master Skills
This requirement also ensures that you have the maximum level possible for your character and all Skill perks.

Oblivion Gates Shut
The maximum possible number of Oblivion Gates shut is 60: 50 random gates, 9 city-related gates, and the Great Gate, outside of Bruma. In order to find all 50 random gates, you will need to explore possible Oblivion Gate locations after completing the Dagon Shrine quest and before you enter Mankar Camoran's Paradise during the Paradise quest. You must close all of the Oblivion Gates before completing the Main Quest: after Light the Dragonfires has been completed, all Oblivion Gates will automatically disappear.

Some players have had problems making the accomplishment page state that 60 gates have been closed. In this situation, you must leave one random gate open until after closing the Great Gate. Prior to closing either of these last two, your accomplishment page will read 58. Even after you close the Great Gate, the accomplishment page will not change to 59. Only after you close the last standing random gate will both that gate and the Great Gate register as closed, giving you a total of 60.  

Horses Owned
To buy all 7, check this list of horses and horse merchants in Cyrodiil.

With Horse Armor Pack official download
Including Old Nag 8 horses could be owned.
''Including Shadowmere and Prior Maborel's, 10 horses could be outfitted with a set of armor.

Houses Owned
To buy all 8, check this list of empty houses, who is selling them and who will furnish them.

Stores Invested In
94 without any official downloads. 100 including merchants from official downloads.''

Without any downloads, there are 99 merchants in the game, all of whom are listed in the Merchants article. Of these, all but five can be invested in. The five exceptions are: Calindil, Edgar Vautrine, Ernest Manis, M'raaj-Dar, and Ungarion.

Downloads add another eleven merchants. It is possible to invest in six of these merchants (Dahlia Rackham, Khafiz, Rowley Eardwulf, Sergius Turrianus, Nilphas Omellian and Niels), but it is not possible to invest in Aurelinwae or any of the Dunbarrow Cove merchants aside from Khafiz.

Warning: To complete this, you need to make sure that all merchants in the game that can be invested in survive until you reach Expert level in Mercantile. Note that Selena Orania in the Bruma Mages Guild dies during A Plot Revealed, Andreas Draconis is to be killed during the Next of Kin quest, Kirsten will no longer converse with you after Mephala's quest, and neither will Etira Moslin and Vlanhonder Moslin after A Shadow Over Hackdirt. Finally, Fathis Ules will refuse to speak to you if you did not side with him in Sins of the Father. As an alternative to reaching expert level, you could make a Fortify Skill spell to increase your Mercantile level to at least 75. This adds the option to invest in the shop, regardless of your base Mercantile level, and allows you to invest in those two stores before completing the related quest.

Skill Books Read
To read all 109 skill books, check this list of where books can be found. Note that the "Books Read" statistic on your character page is relatively meaningless, as it does not have any way of checking if a book has already been read. You can boost this value indefinitely merely by repeatedly opening and closing the same book over and over again. (And of course, there's no way for it to tell whether you've actually read the book, merely opening it and closing it is enough.)

Places Found
There are as many as 367 places which are counted on your "Accomplishments Page" (excluding downloads).



There are more locations to find that have no map marker, and the count on the accomplishment page doesn't increase when these locations are visited.

Great Gate
Isolated House
Melus Petilius' House
Fort Pale Pass
Smuggler's Cave
The Bloated Float Inn
The Sentinel
More on the Unmarked Places page.

There are 2 other places already marked on your map from the start of the game (the count on the accomplishment page will not increase when you visit the locations) including:

Imperial Prison Sewer
Weynon Priory

If you have all of the official downloads as well, the total number of places that you can find that will count as found in your journal (not including the Shivering Isles maps' places), increases by 6 to as many as 373 total. The downloads also add 3 icons to your map for places that start as already found, that can never count as found in your journal. With all of the download places' icons counted into the overall total icons, the total maximum icons that are ever displayed on the in-game map becomes 419 icons, including the 33 that are city-related and the 8 horse stables.

Warning: There are three quest-related locations with impact on the count. If you haven't visited them before doing the quest they will be marked as already discovered on the map marker (compare with Imperial Prison Sewer, above).
Arpenia during Azani Blackheart
Cloud Ruler Temple during Weynon Priory
Sedor during The Stone of St. Alessia

Artifacts Found
This statistic requires successful completion of all Daedric quests.

Grand Champion of the Arena
As the quest The Arena is never completed, this title is the only title not implicitly given by the completion of 199 quests.

Greater Powers
There are 8 permanent Greater Powers attainable by all characters: 7 Heaven Stone powers, and Pilgrim's Grace.

Unique Enemies
There are several unique enemies that you would not come across even if you had completed all the journal quests, so for 100% completion you should seek out and defeat:
The Uderfrykte Matron, aka The Horror of Dive Rock.
The lich Erandur-Vangaril in Lost Boy Cavern.
The Ghost of Perennia Draconis is encountered if you activate the grave outside Applewatch after the Dark Brotherhood quest Next of Kin.
The Spectral Mud Crab may be encountered in Paradise if you do enough exploring.
The Giant Slaughterfish from the Wizard's Grotto leading to Fathis Aren's Tower.
The leveled Rat in Lazare Milvan's house.
The Giant Mud Crab in Greenmead Cave.

Nirnroots Found
There are a total of 306 Nirnroots to be found. The Nirnroot page gives some information on where they are located and how to find them (specifically, it lists all Nirnroots that are found indoors). Otherwise, you can use the site's   to locate the outdoor ones (you must zoom in to level 16 to see them).

Expansions and Official Downloads
With the purchase of the Shivering Isles expansion and the nine official downloads, which includes the Knights of the Nine download, a player may increase their fame, completed quests, places found and may also invest in new merchants. There are a total of 65 new places that can be found, 8 more fame points to be gained, 4 more stores to be invested in and 49 new quests which can be completed. The accomplishments summary has been updated to reflect these additional statistics.

Accomplishments
Quests Completed: 248
Master Skills: 21
Oblivion Gates Shut: 60
Horses Owned: 8
Houses Owned: 8
Stores Invested In: 100
Artifacts Found: 15
Skill Books Read: 109
Places Found: 432 (435 with both the Unofficial Oblivion Patch and Unofficial Shivering Isles Patch)
Fame:  

Shivering Isles
Quests
Shivering Isles adds 31 possible quests to your journal, 2 non-journal quests and 1 quest that cannot be completed.

Main - 17 Quests
 
 
 
 
 
 
 
 
  You choose one (and only one) of these two quests to complete the Ritual of Accession:
 
 
 
 
 
 
 
 
 

Bliss and Crucible - 9 Quests
 
 
 
 
 
 
 
 
 

Settlements - 5 Quests
 
 
 
 
 

Optional - 3 Quests
Can be completed, but not in combination with each other
 
 
''Can't be completed''
 

Non Journal
 
 

Places
Shivering Isles adds 56 marked Places to the game.  The Gates of Madness are already explored, and Xaselm counts twice due to the Secret Entrance.

Retaking The Fringe removes all four markers from the Fringe. When you find them again it adds to your 'Places Found' statistic, bringing the total to 60 places found for the entirety of the expansion.

Knights of the Nine
Quests
Knights of the Nine adds 11 possible quests to your journal.

 
 
 
 
 
 
 
 
 
 
 

Fame
Pilgrimage, Priory of the Nine, Nature's Fury, The Path of the Righteous, Wisdom of the Ages, Stendarr's Mercy, The Sword of the Crusader and Umaril the Unfeathered add one fame point each, adding up to the eight more fame points.

Places
Knights of the Nine adds 3 marked Places to the game: Fort Bulwark, Garlas Malatar, and the Priory of the Nine.  Vanua can't be fast traveled to.

Stores Invested In
Sergius Turrianus can be invested in, despite not offering any services.

Other Downloads
Fighter's Stronghold
Fighter's Stronghold adds one quest, two stores invested in, and one place to the game.

Quest
 
Place
 

Horse Armor Pack
The Horse Armor Pack adds one quest to the game.

Quest
 

Mehrunes' Razor
Mehrunes' Razor adds one quest and one place to the game.

Quest
 
Place
 

Orrery
Orrery adds one quest to the game.

Quest
 

Thieves Den
Thieves Den adds one quest, two stores invested in, and one place to the game which is already marked on your map.

Quest
 
Place
 

Vile Lair
Vile Lair adds one quest, one store invested in, and one place to the game which is already marked on your map.

Quest
 
Place
 

Wizard's Tower
Wizard's Tower adds one quest and one place to the game which is already marked on your map.

Quest
 
Place
 

Notes
The Unofficial Oblivion Patch fixes several bugs. It fixes several quests, resulting in up to eight more Fame points. The patch also fixes bugs with certain merchants being unavailable for investment (and npcs that shouldn't be possible to invest in), bringing the total for Stores Invested In to 96 in the vanilla game. 2 map markers are added for Two Decker Camp and Red Lane Camp, bringing the Places Found total to 369.