The Spider Cave, commonly known as cave, is the name of an area in FoW. The cave itself leads from outside the south of Forge to Beach. The area outside forge, where Nimros the Hunter is found, is generally also considered a part of the "cave" area.
Restoring the Temple of War
This quest, sometimes known as "cave quest" or "seeds", is given by The Eternal Forgemaster after Defend is completed, and takes place entirely inside the cave. 5 Seeds of Corruption spawn at points along the length of the cave, and the goal of the quest is to kill them all.
North of the cave area is the slope leading up to Forge, and to the northeast is the "mageway" route leading to ToS and Lake of Fire. The southern mouth of the cave leads out to Beach. Inside the cave are several Doubter's Dryders, and countless Armored Cave Spider popups. The area to the north contains Shadow patrols, and some Shadow Beast popups. All of the Shadows, as well as the Shard Wolf that spawns here, are hostile to all of the foes inside the cave proper.