Well, I completed the 15 daedric quest (in my diary appears 15 completed missions) and i don`t get the achievement "Oblivion Walker". I have:

- The Black Star.

- Ebony Mail.

- Masque of Clavicus Vile.

- Savior′s Hide

- Volendrung

- Mehrune`s Razor

- Ebony Blade

- Dawnbreaker

- Mace of Molag Bal

- Ring of Namira

- Spellbreaker

- Rose of Sanguine

- Wabbajack

- Skull of Corruption

- Oghma Infinium (i read it)

My quiestions: Is it necesary to get both Hircine artifacts (ring and savior`s hide) and get 16 artifacts insted 15? Is t an achievment bug?