These are the creatures in The Elder Scrolls 4: Oblivion. Choose one.
Sorting creatures for Oblivion was slightly complicated, but I tried to keep all the minimalist traditions of the former Bestiaries intact, while also adapting to Oblivion's peculiarities.
Dremora
Dremora are a class of intelligent, powerful war spirits in the service of the Daedra Lord Mehrunes Dagon.
Churls are the lowest rank of Dremora: obsequious to superiors, ferociously cruel to humans and other Daedra. Like all Dremora, they wield both weapons and magic. Dremora mages may summon lesser Daedra to assist them in battle.
Caitiffs are the second rank of Dremora. They favor a heavy mace and shield in melee combat, and may use magic as well. They often carry potions and scrolls to fortify themselves in battles.
The third rank of Dremora are known as Kynval, or knights. They wield longswords and will not hesitate to use magic or potions to gain an advantage in combat.
The Kynreeve is an officer of a Dremora clan battle unit. They are equipped similarly to the Kynval, with the addition of a shield.
A Kynmarcher is a high officer responsible for a citadel, outpost, or gate, or a commander of a clan battle unit. These dangerous warriors wield heavy claymores, often enchanted, as well as an array of potions and spells.
The Markynaz, or grand dukes, are members of Mehrunes Dagon's Council of Lords. As such, they are among the most battle-hardened warriors in Dagon's service.
The Valkynaz are Mehrunes Dagon's elite personal guard. They are the most dangerous foes you will encounter within Dagon's realm.
Troll
The Troll's uncanny ability to regenerate itself makes it a very dangerous opponent. Although the old wives' tale that it can only be killed by fire is false, there is a kernel of truth there. Fire, magical or otherwise, is one of the quickest ways to put an end to a Troll.
There are also powerful Painted Trolls unique to the quest called "A Brush with Death".
Ghost
These restless spirits can only be harmed with silver or enchanted weapons. Beware of their ability to curse your Fatigue.
There are also Ancient Ghosts that are more powerful.
Like all noncorporeal undead, the Ancient Ghost can only be harmed by silver or magical weaponry, or destructive magic. It can turn itself invisible and strike from an unexpected direction.
Lich
The Lich is the pinnacle of the Necromancer's art. Particularly dangerous to spellcasters, the lich is difficult to harm with magic and has a wide range of high-level spells to draw upon.
A weaker version of the Lich, the Nether Lich is still a formidable opponent, with almost all the same dangerous magical abilities.
Skeleton
The Skeleton is a revenant that can be found wherever the restless dead are buried. Often the creation of Necromancers pursuing their dark researches, they are capable of using all manner of melee weapons, although the most common Skeleton usually is armed with a war axe.
The Skeleton Guardian dimly remembers its former life as a warrior and wields mace, shield, and bow with deadly skill.
The Skeleton Hero's high combat skill makes it a dangerous opponent in melee combat, as it can use a full repertoire of advanced combat moves and is equally adept at blocking.
The Skeleton Champion has one of the highest combat skills you will encounter, and it will often carry a sword as good as your own.
Wraith, Normal
The Wraith can attack with claw, weapon, or magic. Beware of its silence spell, and make sure to bring a magic or silver weapon, because it is immune to normal weapon damage.
The Faded Wraith is the weaker version of the Wraith, but it is deadly enough. Spellcasters need to especially beware of its ability to silence its enemies. Not completely incorporeal like the Ghost, the Wraith is even capable of using (all-too-real) weapons.
Zombie
This mindless animated corpse can sustain an impressive amount of damage before being permanently laid to rest. Zombies also carry a wide variety of nasty diseases, so they are best avoided when possible.
Headless Zombies are even fiercer than their cranially advantaged fellows, perhaps due to their futile longing to regain their lost brains. As with all Zombies, fire is the preferred method of laying them to rest.
The Dread Zombie is easily recognizable by the foul cloud of corruption that it exudes. This cloud may in some way contribute to the Dread Zombie's ability to slowly repair its damaged flesh, which makes it a very dangerous opponent, particularly when attacking in groups. As with all Zombies, fire is the best remedy.