Disclaimer: This boss cannot be found in diep.io no matter how hard you try, so if you find a video about it is fake. However, if you want to see this idea in diep.io(but without attacks just reg boss AI)/Tale of Diep, show some support!
The Fallen Factory spawns at least 10 mins after server creation. It can spawn a total of 25 Drones. Like any Factory, It has one Spawner. The spawner spits out drones at a rate of 1 a second. It can be hard to defeat. The Fallen Factory is also the Fallen Booster's younger brother, as they both once had the same name: Fallen Master. Of course, that doesn't mean he isn't more powerful. In fact, he barely has reign over the Fallen Overlord. Sometimes upon reaching low hp(50% chance), because he is smarter than his sibling, he will choose to let you have him as a pet to defend you. You can still kill him either way for the free exp. Just make sure nobody kill steals. There is also a 1% chance that when he dies, instead of dying, a ghost-like version will float away. This allows the first player to touch the body to get full control over it, and use its powers/high health. Of course, it will be difficult. He, being so powerful and smart, also constructed a portal to the Tale of Diep universe, seeking out new tactics. He found EXACTLY what he needed. Here are his attacks.
Attacks[]
Attacks are done every 30 seconds. If he reaches 1000 hp, there is a 10% chance he will call for help. If he reaches 666 hp and he didn't call before, he will call for help. there is a slim 2% chance of it succeeding
Bullet Scatter: his drones all target people in his FoV, causing every player to get attacked.
Shield(Passive): Drones are sent into a defensive stance(circling the Fallen Factory), they are always shooting in the direction they are looking as they turn.
Shield(LeftClick): Drones are sent into a defensive stance, shooting at the Fallen Factory as they turn. This is his most powerful Shield attack.
Shield:(RightClick): Drones are sent into a defensive stance, with the drones shooting away from the Fallen Factory as they turn.
Double the Power!: Doubles drone size, causing them to become twice as hard to kill, bullets doubling in size, and doing double damage, at the cost of tanks doing double damage to the Fallen Factory. The attack lasts until the end of his next attack.
The drones are my SIBLING!: Same as the Bullet Scatter attack, but the drones also attempt to ram the target player.
Spiraling Drones: Drones are forced to stay still, while firing with auto spin on. Due to the Fallen Factory's intelligence, he uses this as his buffed attack(Double the Power!) 50% of the time.
Regular AI: This is when he is readying his next attack, all drones target one player at a time.
Special Attacks[]
These attacks are used when the Fallen Factory reaches a certain amount of hp.
Double the Drones!!!(500 hp): Doubles max drone count and spawn rate.
Copying others is fun(2500 hp): It's next few drones are clones of all the players attacking it. The evil copy is opposite the player, and as such, will move the opposite direction the original is moving. It's fire is still AI controlled.
Double TIME!(1500 hp): Perhaps his most powerful attack, his defense and attack and regen is doubled for the sake of survival.
Help Attacks[]
These attacks are used in an attempted to call another boss to help it.
Sibling Call: the Fallen Booster is summoned to help the Fallen Factory.
Devils Call: If successful, both the Fallen Booster and the Fallen Overlord will spawn.