Witches always try to stay away from the attacker, so they can burn you with their powerful fire missiles at a distance. They can make you look like a Green Frog.
Witches are women with strong magical abilities. They are frequently found with Amazons and Valkyries, and have become very involved with cult activities on the Shattered Isles. Some people believe that witches are leaders of the amazons and valkyries. Witches provide poor loot. Although Witches only use fire attacks, they are not immune to fire.
Be careful because they can attack you even before you see them. If you are alone, do not attack more than one witch, since they can damage you fairly fast.
Mages: would best use either Wand of Inferno or Necrotic Rod, otherwise either using explosions or GFB depending on how many there are. If you are planning to hunt them, you can summon a Fire Elemental as a mage. Knights: should just run up to them and kill them. Try to block her in a corner with other objects or monsters, so she can't run away, and shoot Fire Fields. A knight can kill a witch with skills 55/55 very easily, but just watch out for their fire fields, as they can become a pain if killing more than one witch at a time. Paladins: should stand still and kill them from a distance.
If you block them in a corner, they will usually stop spamming their fire attacks and use their weak melee instead.