Similar to the best armor, Infernax hides the best weapon behind some pretty high walls. Unfortunately, unlike the armor, which can be used to make later runs cheaper and easier, the best weapon is at the very end of a long quest and even then it’s hidden.
How to Get the Best Weapon in Infernax
The best weapon is hidden in the optional dungeon in Combbelton Cemetery.
This place is only accessible when you have every ability or at least get far enough to enter the jetpack cheat code. However, finding it is not the hard part, it’s getting inside the gate.
The trick, sadly, is to progress in either the knight or cult storylines. Out of the two, I’d say cult is easier, though both are required if you want every trophy/achievement. To enter the gate and find Robert, you need to fully gain one factions trust.
This means you need to do practically everything good or evil on a single run, along with going to each base and doing the members optional quests (the ones that tell you to return). At the final one you’ll be told to go to this location to find the boss. However, this is just the first step.
Obtaining the Weapon
Getting into the building is the requirement to start the quest that gives the question mark item, The Necronomicon. What you might not realize is on the right side there is a breakable wall that you can open.
Behind it is a new dungeon, the Hidden Crypt, which is a rather short adventure.
At the end there is a new greater demon, the Lord of Maggot. He is a simple boss, he spins around and you smack his face until he dies.
Killing him will unlock the gate and give the final weapon upgrade and a nice trophy/achievement for your trouble.