Kat will come up with plan to save herself. Follow her, and when she sprays the red markers use demon pull to bring down the ceiling. Keep following Kat and using demon pull when she indicates to get through the walls. Follow her through the hallways, avoiding SWAT teams. Eventually, Kat will be trapped by a guard, use the marker she sprayed to topple a shelf down to protect her.
Kat will finally lead you to Virgil. Dante’s twin brother is under attack. Fair warning, this fight is going to take a while, so make sure you are adequately stocked up on orbs and other health necessities. First take down the butcher going in close for the attack then avoiding his blades.
Brace yourself for a few rounds here. For starters, you’ll face a bunch of stygian and two ravagers. Just keep the enemies in front of you and don’t let yourself get surrounded. Now you get three ravagers and a butcher. Try to get the ravagers one-on-one with demon pulls, watching out for the butcher’s ranged attacks and the charging chainsaw attacks from the other ravagers. Once the ravagers are done, take out the butcher.
Now, a score of rage spawn will swarm you. Osiris was made for this work. Keep the rage spawn at bay with the scythe, which shouldn’t be too hard. Now, about four demon shards will come up through the floor. Blast them all if you can, but be ready to dodge out of the way. Virgil will give you a new gun class, Revenant, which is a blunderbuss shotgun. Use it to take out the five more demon shards that come up through the floor.
Another round of rage spawn will pop up. Again dice them up with Osiris. Then a bunch of stygian and handful of harpies will attack you. Use Osiris to deal with the stygian as much as possible, watching out for the harpy attack. You can always tell a harpy attack is coming as they will make shrill screech before attacking. When they swoop in, duck out of the way quickly. After whittling down the stygian numbers, another batch will pop up, then another batch after that one. The same is true of the harpies.
Just when you thought it was over, two rages come to play. Use the same strategy as before, juggling one while watching the other. Once you’re done with them, the mission is over.