King Otto's Monster or The Monstrosity is an enemy in Chapter 8 and the final boss of Wolfenstein: The Old Blood.
Monstrosity was a creature created by the alchemists of King Otto as a weapon of war from the assumed parchments of Da'at Yichud ancient genetic technology. When Otto saw the destruction that the monster could cause, he decided it was an abomination. He burned Wulfburg and entombed the monster alive. Later the Nazis seek the secret of King Otto (without knowing that in fact it was the monstrosity) in Wulfburg, where they began digging for clues left by King Otto. Once they reached the chamber, the Nazis triggered dynamite and caused an earthquake that destroyed part of Wulfburg, killing civilians and Nazis in the area. B. J. Blazkowicz reached the monster's lair, but was captured by Helga, who finally freed the monstrosity. Helga tried to control the monster but failed, and it murdered her and Schreiner. Later it fought Blazkowicz, but was eventually defeated, ending the secret of King Otto forever.
- To kill it, it is recommended that you shoot at its mouth for maximum damage.
- It is blind, and only attacks if it hears sounds. Try to stay silent if you're not attacking it.
- The upstairs floor of the arena has all the supplies needed for this fight. Even if you run out of ammo, more will drop in for you to restock.
- Use grenades to distract the monster.
- Use the Kampfpistole to deliver the most damage.
- As the fight wears on, Nazi soldiers, and later shamblers, will pour into the arena from the upper floor. Keep a distance from soldiers, as the monster will attack them as well. Most of them will be instantly killed, while a few will take enough damage to become shamblers. Again, use grenades to also deal with the shamblers, as gunfire will attract the monster.
- When the Shamblers start to appear, use the Handgun with the suppressor attached to stealthily take them out without alerting the monster.
- Don't get close to Shamblers, because the monster also responds to their melee attack, and since they're closer to you, you'll also get damaged when it attacks.