The Witchhunter is a pre-made class in The Elder Scrolls III: Morrowind and The Elder Scrolls IV: Oblivion. In both games, Witchhunters serve as adept anti-mage combat artists. The Witchhunter uses various schools of magic and marksmanship to combat foes. To assist its combat prowess, the witchunter excels at lockpicking and athletics. Since the skills of the witchhunter are skills which both Argonians and Bretons are proficient in, they make the most effective Witchhunters. Altmer, excelling at magic, also make effective Witchhunters, so long as they wield enchanted items that resist magic or elemental damage.
Witchhunters are dedicated to rooting out and destroying the practices of dark cults and profane sorcery. They train for martial and magical war against vampires, cultists, necromancers and their summoned creatures.
Bows, both real and bound, are the standard weapons of any Witchhunter. A skilled Marksman can shoot a mage while avoiding any incoming spells and outrun any slow Daedra while peppering them with arrows and spells.
Also essential to the Witchhunter is the magical skill of Destruction. These spells can augment arrows and are quite effective at exploiting or creating weaknesses of the enemies, as well as disintegrating their armor and weapons. Close-range Destruction spells, such as Cold Touch, gives Witchhunters an advantage in melee encounters, whereas projectiles would be less effective.
In conjunction with these two skills, Athletics is very useful. It allows the Witchhunter to keep a distance between themselves and enemies. As one of the few classes without either an armor skill or Alteration for shield spells, keeping away from damage is a useful strategy.
As mentioned above, the Witchhunter lacks any armor skill. Thus, it is important they make use of Conjuration. Some Witchhunters may consider this school of Magic as the tools of the enemy and creates a risk of contamination, but these spells are so useful that no Witchhunter can do without. Summoning a creature to take the melee damage instead of the caster, or binding a cuirass on oneself are both very effective when taking on fast and powerful enemies, such as Clannfears. Turn Undead is also a great spell for a Witchhunter, especially when cleansing a lair of necromancers.
The other magic skill of the Witchhunter is Mysticism, primarily to Dispel any summoned creatures from their summoner (simply hit the necromancer with a Dispel on target and the summoned creature will disappear), but this skill also comes in handy to Detect Life and Soul Trap enemies. The more powerful spells of Reflect and Spell Absorption are also useful later in the game when going up against powerful warlocks.
When investigating a potential vampire or necromancer, often evidence of their true nature or habit is behind locked doors or in a locked container. The Security skill allows any Witchhunter to open such locks.
Finally, a Witchhunter knows how to use the secrets of Alchemy. Poisoned arrows and a few powerful potions can be all it takes to tip the balance in favor of the Witchhunter. Potions of Shield, Restore and Cure Disease are the most useful when fighting vampires or necromancers, as are the Damage Magicka and Silence poisons.
Bretons make effective Witchhunters due to their proficiency with both defensive and offensive magic. The Breton's innate ability to Resist Magic gives them extreme defense against hostile magicka-users.
Altmer, while weak to Magicka, boast stronger magical power and a vaster Magicka pool. Dunmer gain bonuses to Marksmen and Destruction, making them adept offensively for the Witchhunter class. Their proficiency with Light Armor helps counter the Witchhunter's vulnerability to melee attacks.
Lastly, Argonians excel at Illusion and Mysticism, two helpful skills for the Witchhunter build, while their experience with Alchemy allows them to craft poisons to dip their arrows in. Poisons that damage magicka help when combating mages, forcing them to rely on physical prowess in battle.