Baba Yaga

Probably the easiest of the three witches, as long as you can get rid of her elementals and drain her spell-power away. She has large hp, but doesn't hit too hard. From recall, go west, north, east until the second south, south until the second west, west, northwest, southwest, south and search in this house. A down should appear. Head down, all north, all east, south, all east, and prepare here. Get dispel magic, an orb of negatation or whatever else with the spell ready. Head north until you hit the dizzy room. A spider will begin casting a spell, dispel the room or start casting quickly so it casts after him. If you succeed the room will dispel, if not you'll need to stumble around until you make it out. Head west, the first room west is NPK, the second is CPK so make sure you don't get CPKed here. Go west through the CPK and you'll meet Baba Yaga. Most of the time she'll be in CPK, so attack her then flee, she'll come after you within a couple of minutes. If she doesn't come after you, do it again.

Once she finally comes out, it's time to fight her. When you first attack she'll automatically try silence you. To avoid this, just use a psionic to do the first attack, and if needs be have them flee once the tanker is in combat.

She'll die slowly, keep her plagued and poisoned.

You can loot a small wicker man, a broom of Baba Yaga and the rattleskin scroll from her which contains the spell reflective fireball.