The Terrible Tyrant Quest in Hollow Knight: Silksong can be found on the Wishwall in Bone Bottom. For this Quest, you have to hunt down the Skull Titan, who’s located at the Marrows. He’s a fairly simple boss, but will take some time to beat due to his repetitive moves and large health pool. First, you need to find where he’s holed up. After that, you can get to defeating him. This guide will help you find and defeat the Skull Tyrant boss as a part of the Terrible Tyrant Questline.
How to Find the Skull Tyrant

To find the Terrible Tyrant, start at the area in the Marrow, which is located close to Deep Docks, as shown in the image above. From there, climb up onto the platform, then continue up the narrow path.

Once you’ve reached the top, the area will be filled with darkness. From there, keep heading left and avoid all the spiky enemies out to get you. Continue on the left path until you come across another narrow path to the top, at the end of the path.

Here, you must jump and climb up to the top. There’ll be an opening just before that in which you can drop down, so avoid it completely. Climb up to the top and keep heading left.

As soon as you head left, you’ll find yet another opening upwards. Here, jump and climb up the platform, then head right, where you’ll face a spider-shaped skull enemy. It’s a normal enemy, so you don’t need to worry about it.

Once you’ve defeated or dodged the enemy, keep heading right to find another opening at the top, which leads you to a completely new area. Climb up top to access it.

As soon as you enter the new area, head left, jump up to the platform on the right. Keep heading right and you’ll eventually find the Skull Tyrant boss waiting for you in the dark Marrow caves. Hit the boss to wake him up from his deep slumber, and progress the Terrible Tyrant quest.
Defeat the Skull Tyrant

The final part of the Terrible Tyrant Quest in Hollow Knight: Silksong involves facing the Skull Tyrant boss, which is a fairly easy boss to defeat. Once you’ve defeated this boss, you’ll obtain an item called the Crown Fragment, which you require to complete this Quest. You need to deposit it at the Wishwall in Bell Bottom, the place where you first started the Quest.

Head back there and deposit the item to get a Heavy Rosary Necklace as a reward for your troubles. This will mark the end of the Terrible Tyrant Questline. Doing these side quests always helps – it adds to the lore for one, and also gives you useful collectibles and upgrades, like what you get here for the Lost Fleas questline, which gives you the option to completely skip a particularly irritating boss (looking at you, Moorwing!) in Hollow Knight: Silksong