The Doom Eternal Icon of Sin boss is a great callback to the second game in the series. That was a tricky fight back then, especially if you didn’t know immediately what to do. Doom Eternal tells you how to beat this new iteration of the Icon of Sin, but it’s up to you to actually do it. So how do you beat the Doom Eternal Icon of Sin boss? Also, obviously, big spoilers ahead. Although you’d think Bethesda wouldn’t put the last boss in its trailers, but whatever.
Doom Eternal Icon of Sin boss | How to beat
The Icon of Sin has two phases where you have to shoot his armor off and then shoot his fleshy bits in another arena. The problem is that it spawns in a lot of big ol’ demons at the same time, meaning you need to be constantly juggling who you’re shooting at.
While there are some caveats, the general strategy is to keep moving and not focusing on the “smaller” enemies. Fire off shots at the Icon of Sin in bursts when you’re not being bombarded. If you stop and wail on the Icon of Sin or some Cacodemon, something will blindside and probably kill you if you’re playing on harder difficulties. The best weapons to use are the Ballista, BFG, rocket launcher, and chaingun as they can do a lot of damage very quickly.
However, that doesn’t mean you should ignore the enemies outright. Chainsaw demons to get ammo and then Glory Kill some of the smaller ones to get health back. You can use three chainsaw fuels to kill some of the bigger demons to get them out of the way quickly. The Crucible sword is great for the fiery Baron of Hell enemies. If they are in your path that you’ve been circling around, then it might be a good idea to take them out after using the Flame Belch or Blood Punch for some resources. Ignoring too many of them will clog up your paths.
Chainsaw fuel respawns so the best strategy is to continually loop around the battlefield in a circle (while also changing what level you’re on) and grab gas tanks and anything else in your way. Take note of where the jump pads, portals, and swing pipes are as they are a great way to ditch enemies on your tail if it gets too hot. Run in a circle, constantly go from low to high elevations, and take shots at the Icon of Sin as you’re moving.
Don’t hoard your ammo either since this is it. This is the last thing you need to kill. There’s no reason to keep BFG ammo.
If your health gets too low and you need a quick bailout, there is a supercharge power-up at the top of the arena of the first phase. You’ll have to swing on some pipes to reach it. Grab this when your health gets low, as it will top your health and armor off, which is a huge lifesaver.
The second phase is actually pretty easy if you’ve utilized that strategy. Just do the same thing and circle around, dash out of danger, don’t focus too hard on the fodder, and shoot the Icon of Sin in the parts you haven’t shot off yet. You can tell which parts are vulnerable because they glow when you shoot them. There is also a supercharge power-up in the middle, so be sure to grab it if you’re on the brink of death.
That should be it. The whole game trains you to keep moving and shooting and this final boss is the biggest test of that philosophy.