Nest of the Emerald Widow
Nest of the Emerald Widow is the first dungeon that is not staffed by people who can be reasoned with, and the difference lands hard. A green cavern system has been converted into a breeding operation, wall to ceiling, and the conversion was thorough. The silk is not decoration and it is not incidental: it is infrastructure, laid down in lines that carry information, and every line you walk through reports you.
That is the horror of the Nest rather than the venom. You are never ambushed, because nothing here needs to ambush you. The drones and spiderlings at the entrance are the brood's cheapest tissue and it spends them freely to find out how you fight. By the time the Shadow-Silk Stalker and the Chitin Colossus arrive, the answers have been collected and the encounters are shaped around them.
Encounters
Tier 1
Web-Snared Drone
Tier 2
Emerald Spiderling
Tier 3
Silk Trapper
Tier 4
Venomfang Hunter
Tier 5
Broodmother's Consort (Mini-Boss)
Tier 6
Corrosive Weaver
Tier 7
Shadow-Silk Stalker
Tier 8
Chitin Colossus
Tier 9
Widow's Herald
Tier 10
The Emerald Widow (Final Boss)
The final boss
The Emerald Widow is enormous, patient, and entirely uninterested in you as an opponent. Her Herald announces you, which is a courtesy paid to livestock. She fights the way a landlord evicts: without urgency, from a position she has already prepared, and with the confident expectation that the matter resolves itself if she simply continues.
Before you enter
The recommended level is 10. Treat it as a starting point: farm earlier tiers, upgrade gear, and adjust your pet when a boss stops you.
Difficulty inside a dungeon comes from one number that climbs with the tier, and the step between tiers is a large fraction of the gap between dungeons. So a wall at tier 7 here is not a signal to grind this dungeon harder - it usually means the opening tiers of the next dungeon are a better use of the hour, and you come back with the gear they dropped.