Tal Rasha's Chamber is the final area in Act 2. A small chamber found in the True Tomb of Tal Rasha, it has no direct access. To enter it, one must insert the Horadric Staff into the Orifice in the final room of Tal Rasha's Tomb, which will cause a small passage to open on the wall.
After entering the zone, players are immediately beset by Duriel, the boss of Act 2. However, he is not the actual final enemy in the act - once players defeat Duriel and proceed past his room, they'll be immediately ambushed by a pack of Poison Spitters led by Flower Prowler. Tyrael is present near the Binding Stone and will open a portal to Lut Gholein.