The following chapter contains information and tips on defeating the first boss of Dead Cells. The subsequent sections will allow you to learn the location, where you can find the boss, the range if his attacks and possible strategies of defeating him.
Where to find the boss?
The Incomplete One is the first of the more powerful enemies that you'll have to defeat in order to progress in the game. You can find him in The Black Bridge, where he's the only enemy. After defeating him, you have to get to The Fog Fjord and resume your fight. You can get to the former location in a number of ways - directly from The Ramparts; The Old Sewers; or The Prison Depths.
How to defeat him?
The fight with The Incomplete One is pretty long and monotonous. He will always try to attack you with a physical strike once you get too close. The boss will also be constantly trying to close in on you, and if you reduce his health even slightly, a wave of flames will appear on the bulk of the arena. The only way to avoid them is to jump over.
This boss is characterized by high resistance to physical damage, but he's also very susceptible to all effects that you can cause. Regardless whether it's bleeding, poison or incineration, you will be able to defeat him with less effort and less risk. That's why you should forget melee weapons that don't cause any effects, for the sake of this fight.
During this fight, you will find that poison daggers, bows and, most of all, an additional turret (which will effectively distract the enemy) will come in extremely handy. Freezing grenades, bear traps that can immobilize him, and bleeding or fire weapons will also be useful. Even if you only have some of these items, you should be able to win - just focus on avoiding damage.
This fight is not easy: the enemy often conjures aura and leaps towards you. you have to constantly be on your guard, and only close in if you have no other choice. His attacks are clearly telegraphed and very ponderous, so a weapon that will allow you to quickly overwhelm him with multiple hits (before he counterattacks) is absolutely mandatory.
Defeating this enemy allows you to get to new locations available in the game. Apart from that, you get over a dozen cells, some treasure that converts to gold, and another weapon.