Step 1: Shoot Graves

Once Spawned in you'll see 4 Graves (One With Each Characters Name) Shoot them From Left to Right(2 > 3 > 1 > 4).

Step 2: Curruption Engines

Find all 4 Curruption Engines and activate them, Activating One will Start a sort of Lock Down in which you'll just have to Survive to Complete.

Step 3: Trap The Apothicon

After all four are on Head through one of the Now activated Portals and Interact with the Console As the Apothicon is Flying By to Trap it.

Step 4: Keeper Protector

Find All 3 Keeper Protector Parts around the Map (1 In Each Section, Excluding Spawn) and Build it at a Keeper Protector at one of the 3 Wall Locations.

Step 5: Apothicon Servant

This Will Require you to Hit the Mystery Box Until you get the Apothicon Servant, Now Find 5 Floating Gems and Shoot them using the Apothicon Servant, Then go Pack A Punch it.

Step 6: Triangle Rock

Find the Triangle Rock at one of the Launch Pads, Once Found go Activate the Keeper Protector and Bring Him to that Rock/Launch Pad, Protect him for 3 Minutes, And Pick up the Disc.

Step 7: Little Arnie

This Will Require you to Hit the Mystery Box Until you get Little Arnies, Go in the Apothicon Servant and throw Little Arnie's' in all 9 holes (3 at a time) and kill all Margwas that Spawn.

Step 8: Bone Collecting

Shoot all 6 Rocks that Spawn Around the Map with a PAP Gun and then Shoot the Bones that come out with the PAP Apothicon Servant From Step 5, Shoot the Body Upstairs in Nahct and pick up the Disc.

Step 9: Laser Traps

Go to all 4 Curruption Engines and Activate the Trap, Point Each of the Lasers at one of the Rocks in the Sky which it kick you off the Trap and leave the Laser there, Now Move on to Step 10.

Step 10: Follow Sophia

Head to Nacht and Interact with Sophia in the roof, Follow her to Kino and take the Teleporter, Pick Up the Book off the Bed and Place on alter Infront of Teleporter.

Step 11: 4 Gate Worms

Find and Collect 4 Eggs around the Map, Place the Eggs in the Middle of the Apothicon and soul collect, Pick up the Gate Worm after Soul Collecting Now Find the Location Where you Hear Beeping and Place the Worm.

Step 12: Boss Symbols

Head to the Film Room Upstairs in Kino Stand on a Symbol, while in boss Room watch book and Memorize Symbols, Interact with those symbols in Order in the Back of the Room and Pick up Summoning Key that Falls Down.

Step 13: Collecting 7 Items.

Find and Throw The Summoning Key at 7 items Around the Map, and Head Back Towards the Upstairs Kino Room Where you Can Start Boss Fight by Standing on the Symbols Again.

Step 14: Boss Fight

Once in Boss Room Place the Summoning Key in one of the 4 Alters and Kill Zombies Near it, Pick it Up and Throw it at Sophia in the back middle of the Room, Shoot Shadow Man and Interact with Book.