The areas in Act 4 are:

The Pandemonium Fortress - the main starting area.

Outer Steppes - lots of cliff lurkers and doom knights. No sub-areas.

Plains of Despair - where Izual, the fallen angel, is.

City of the Damned. More monsters.

River of Flame - this is very short, just little pathways through fire. Not even really a maze. Great if you have ranged weapons to shoot across the fire.

Chaos Sanctuary - this is the area a lot of people have trouble with. It's not big - just one stone cathedral with three 'arms' on it that hold the 5 seals. There are TONS of nasty monsters though. When you trigger all 5 seals, Diablo appears and you have the final battle (except for the expansion set of course!)



Diablo 2 Walkthrough
Walkthrough Master Index