|“||Huh? That monster's name is Claus? Its name was Claus?! That almost sounds like a person's name! But now it's my robot. Not even a fragment of life remains inside it.||„|
|“||Dad. It's me. Claus. I told Lucas to come too, but he's been crying at Mom's grave all this time. Dad. I'm gonna leave this apple here. The core might be hard, but… The core… The core might be too hard to eat, but be SURE you eat it! I'm gonna get stronger. …I'm gonna get so strong even Dragos won't stand a chance against me! Dad… I…||„|
|~ Claus to father Flint in his cell|
Claus is the secondary and final antagonist of Mother 3. He is a cyborg who is the commander of Porky Minch's Pigmask Army, as well as the twin brother of Lucas (the main protagonist of the game). He is actually controlled directly by Porky.
After Claus' mother, Hinawa, was killed by a Drago, he leaves Tazmilly Village and ventures into the canyons to find and kill the Drago in order to avenge his mother's death. When Claus' father, Flint, hears of this, he leaves to look for Claus. He encounters and defeats the mechanically reconstructed Drago that killed his wife, but Claus is nowhere to be found. He was presumed dead.
In actuality, Claus was beaten within an inch of his life when he was found, captured, and killed by Porky and his Pigmask Army. Porky's ultimate goal was to have the seven Needles pulled to have the world 'reborn' in his own image, but he did not possess the power to pull them. Porky saw the potential in Claus, and had him killed and reconstructed with robotic attachments, burying his memories deep inside of him. Breaking his will and his mind, Porky turned Claus into the commander of the Pigmask Army. Before fighting Porky, he reveals that he actually controlled the Masked Man, and presumably continued to do so from inside the Absolutely Safe Capsule.
The sleeping dragon below the Nowhere Islands would awaken and destroy the world if the seven Needles are pulled. The world would then be 'reborn' based on the heart of the person who pulled them. If a man with good intentions pulled the needles, the world would become a good place. Likewise, if an evil man pulled the Needles, the world would descend into chaos.
Claus set to work pulling the Needles on Porky's behalf, but it would seem that Claus had neither good nor evil intentions, as the Magypsies, guardians of the Needles, noted that the puller seemed to have no heart.
Lucas was the only other person capable of pulling the Needles, and he hurried to pull them before Claus. After Porky was defeated, Lucas encounters Claus, who is about to pull the final Needle. Claus fires a bolt of electricity, knocking his friends unconscious, but leaving Lucas unscarred because of his Franklin Badge.
Throughout the battle, Lucas is unable to attack Claus, who unrelentingly assaults him with his sword and arm cannon. Hinawa's voice calls out to Claus, urging him to end the battle. This initially does not phase him and later Flint who intervenes in the fight but also fails reach his son, but as Hinawa's voice continues throughout the fight, he begins to be overcome by his long-thought-gone emotions. In the end, he takes off his mask and fires an immense bolt of lightning, which is deflected by Lucas' Franklin Badge, essentially killing himself. Though mortally wounded he had enough strength to share his final moments with his brother, he apologizes and thanks Lucas before claiming to "go to that place Mom is" but assures him that they will meet again before taking his final breath.