Vulcanus / Hell
The Lava dungeon behind the Hell Gate in Katan — level 200 to enter, no quest line and no key, plus every drop and combination.
How to Enter
Level 200. That is the whole requirement — no quest line, no key, no difficulty to pick.
The way in is Entrance to Hell Dungeon, a warp gate standing at 115122, 59643 in Katan. Step onto it at level 200 or above and it takes you straight down; below that it turns you away.
The materials for Lava Gear drop inside.
Drops
Monster drop table
Trash mobs and bosses drop the dungeon currency and loot box:
Lava Drop 
Lava Box
From the Lava Box
Opening a Lava Box yields the elemental shards (plus a Typhon Shard):
Lava Physical Shard 
Lava Magical Shard 
Lava Deffence Shard Typhon Shard
Combinations
The drops above combine into the crafting reagents used for Lava gear (see the Lava Gear guide for the exact recipes):
Lava Cube 
Advanced Lava Cube 
Lava Feather Typhon Crystal Typhon Scroll