Tyrant of the Skies is an extremely powerful boss in Blox Fruits, and he drops Moonstone, Fire Feather, Feathered Visage, and Liberator of the Sky title. If you want to spawn this boss, here is how you can do that.
Blox Fruits Tyrant of the Skies raid boss location

The Tyrant of the Skies raid boss is located on the Tikki Outpost island in the Third Sea. Once you are on the island, head over towards the middle-left, where you will find a new location, and this is where the boss spawns. However, spawning the boss requires you to do a few things, and here is everything.
How to summon the Tyrant of the Skies raid boss

When you are at the location, look for the eagle on the sides. To summon the boss, you have to make both the birds’ eyes glow. You can do that by keeping on killing NPCs in the corresponding areas of these birds' eyes.
This means that you have to head over towards the direction of each of the eyes and kill the NPCs in that area. In my experience, you have to kill 100 NPCs to make the eyes glow, but that might vary.
Now that you are done with that, and the eyes start to glow, you can successfully summon the Tyrant of the Skies boss. Head back to the area with eagles and start smashing the vases on the sides as fast as you can. Keep repeating and destroying these vases, and the boss will eventually spawn.
Before spawning the boss, ensure that you have other players or friends to help you defeat the boss, as he is extremely powerful and can easily kill you in 3 to 10 hits. So, ensure that there are enough players to help you, and then summon the boss.
For more Roblox Blox Fruits guides, check Blox Fruits Gravity Fruit Secret Moves & Upgrade Guide here on Pro Game Guides.