When you've taken another third of Set's health, as shown in Phase Two, Osiris releases him, and the 3 Marks of Set reappear, along with a horde of larger, tougher enemies.

AMMIT also crawls up onto the corners of the platform now and then. As in phase two, if you use items that confer fire resistance and don't stick around when she starts belching fire, you should be OK.

NOTES: There is a little more info in the main walkthrough about combat strategy for both single-player and co-op mode in phase three. Phase three is also a good time to attempt the Challenge: Knock 5 Enemies into the Central Pit. See the challenge notes for details.

As in the previous phases, the main goal is to destroy the 3 Marks of Set and re-light the beacons. Again, the order in which you light the beacons doesn't matter. Use the Staff to close any of Marks.

Then use the torch to light the beacon.

Hurry to the next beacon and repeat the process.

You should now have two beacons lit.

Run/roll to the third corner, destroy the Mark...

...and light the third beacon. If you were waylaid by enemies and took too long, go back and repeat the process until all three beacons are lit simultaneously.

Osiris once again immobilizes Set so you can finish him off. Equip the rocket launcher...

...and let him have it. When you've reduced his health bar to zero, it's t's GAME OVER!

[Part 2 | Return to the Tomb of Set Walkthrough]