We first got to know Hundun thanks to fans deciphering the Hidden Trophies and Steam Achievements, revealing some of the missing locations that are not yet on the Known Locations list. Hundun hangs out in the Sunken City, a spooky lair that can only be reached with a very specific mount. Even the jetpack can't get you there.
To reach the Sunken City you will have to unlock Duat et retrieve the tablet of fate from one of the bosses there. The Tablet of Fate is dropped by Osiris, so be sure to detonate a few bombs on him. Sticky bombs do the trick. We've got all the information you need to join Duat in a separate guide here.
The guide below explains everything you need to do next.
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How to fight Hundun, the secret boss | Sunken city location
To access the last hidden area, The sunken city, you will have to reach Duat and retrieve the Tablet of Fate. The Sunken City's toughest final boss is Hundun, and we really don't know what it takes to beat that stuff - a jetpack and a shotgun, to begin with.
To access it, follow these steps. For a quick reminder, I'll go over the steps how to join Duat.
- Requirement: Need to get the Tablet of fate to start the Sunken city path.
- Collect the Eye of Udjat (1-2 / 1-3) from the chest with the Golden Key.
- Buy the Hedjet on the black market.
- Go to the bottom cave in 3-1 and climb to the top to find the Ankh.
- Enter the temple of Anubis (4-1) through a lower door in 3-1 and kill Anubis to get the scepter.
- Find the Golden City gate in 4-2. It will open with the Scepter and the Hedjet.
- Find the High Altar in the City of Gold. Fall from a great height to die so that your body lands on the altar. If you have Ankh, you will live again.
- Reappears in Duat. Climb up to (there is no time limit) and kill Osiris to retrieve the Tablet of Fate. Then kill Anubis to get out.
Once you have the Tablet of Fate, you are ready to reach the Sunken city. It's still very difficult, so be prepared for a long descent. Be prepared to play very, very carefully.
How to access the Sunken City and fight Hundun:
With the tablet of fate, travel to 6-2 and find the room with the strange figurines. Open your journal and check the tablet of fate - it gives you three randomly generated clues. One clue describes the condition of the figurine, one describes the material, and one describes the symbol. Collect the figurine that matches the three descriptions.
Descend to 6-3 et pose the figurine. It will open up and happen again Qilin, a flying mount. Now you have to reach 6-4, the ultimate boss arena. Qilin can take four hits in total, so play safe.
In 6-4, you will have to kill boss Tiamat or not. Either way, fly with the Qilin lasers and dodge to find an optional secret exit door at the very top. Then you can enter the spooky Sunken city.