The Poisoned Spring - Act 1 Side Quest
Start Location: Village of Tegea
Quest Location: Tegea Forest
Objective: Defeat the arachnids in the cave then speak with Pegaea outside
The Poisoned Spring quest starts by speaking with Olorus in the Village of Tegea, a town in Act 1. This quest is one of the few quests in the game which will grant the player a permanent reward on each difficult that it is completed. On Normal it gives you +75 HP, Epic it gives you +150 HP and on Legendary you'll receive +250 HP for completing the quest.
For this quest the first thing you will want to do is travel southwest of Tegea until you find a cave with a friendly water nymph outside of it named Pegaea. Speak with Pegaea to update your quest then head inside and kill the packs of spiders in the back of the cave. You can tell quest mobs apart from other mobs in this game because they will have purple names and typically have white auras around their bodies.
Once every quest mob is defeated your quest will update and you'll want to return to Pegaea to turn it in.
Note: The Spider enemies you fight during this quest can also drop Deathweaver's Legtip which is an extremely good Rogue Monster Infrequent.