Diablo II/Act I

The Rogue Encampment
This is the starting area, as well as the first town in the game. Only two exits exist, one that heads into the wilderness and one that takes you to the second act if the sixth quest has been completed.

Akara
Akara is the town magic user; she will sell potions, tomes, scrolls, staves and orbs and other related items. Talking to her will instantly fill your health, stamina and mana to their maximums.

Kashya
Kashya is the town mercenary merchant. She will allow you to recruit rogue archers of the sisterhood (one at a time) to join you in battle.

Charsi
Charsi is the town blacksmith. She will sell you weapon and equipment and can repair your items for a fee.

Deckard Cain
Although he won't show up until you or the creator of the game (if in Bnet) has done the Search for Cain quest. Deckard will any unidentified items in your inventory for free, he will also guide you on various quests by giving you information and he will follow you to every act within the game.

Warriv
Warriv will offer to take you in his caravan after you defeat Andarial. By doing so you will enter the eastern desert lands and be within Act II.

Quests

 * Den of Evil
 * Sisters' Burial Grounds
 * The Search for Cain
 * The Forgotten Tower
 * Tools of the Trade
 * Sisters to the Slaughter

Catacombs IV
This is Andarial's lair. It has some slight variation within the entrance but where she lies is, of course, a template area. It's laid out with an entrance containing dark ones and some shamans accompanying them. On the eastern side is a double door that opens into Andarial's throne room; within it are zombies, dark ones, big guys that spit balls, and Andy in the northeast. In the northwest there's usually a healing shrine, in the southeast a tomb you can raid.