Torchlight 2 Walkthrough Part 17: Some Assembly Required

Now that the Alchemist is gone, he has closed the gate. You need the Automaton Keybot to open up the door, but he's missing his battery. You'll have to head out and find one before you can get through the door. This route will take you down to the Rotted Path area and into and through the Blightbogs. This area is full of venomous creatures who can spit poison your way, so you will want to keep on the move at all times. The fumes that spew forth from enemies will linger on the battlefield for a while, and they'll poison you as you walk through them.

The Blightbogs are a massive area filled with flaming floor vents and powerful enemies. You might stumble upon powerful Champion enemies here, where they wander in groups. On the way, you will need to find a red soldier with a question mark on his head. Speak with this guy to get the quest called The Cave In. This quest is necessary to complete the Some Assembly Required mission, as it will give you dynamite.

Head to the next walkthrough to complete The Cave In, and then return to this quest to complete it with the dynamite.