Sentinel Batteries allow you to open more areas of the Fortress of Doom. This Doom Eternal Sentinel Battery Location Guide tells you where to find each of the Sentinel Batteries we have discovered so far. Sentinel Batteries are special, rare items that once found, can be installed at various locations in your ship, the Fortress of Doom.
Once you provide The Fortress of Doom with more Sentinel Batteries, more areas of the fortress become unlocked. Sometimes this simply allows you to access deeper parts of the ship, other times it unlocks new upgrades for your armor, more weapons, there’s a lot hidden behind the Sentinel Battery collectibles.
Important: From level 3 onward, each level has 3 challenges to complete. If you complete all three challenges on a single level, you will get a Sentinel Battery. Those are not included in this guide.