Claus

Claus is a boy living in Tazmily Village, appearing in Mother 3. He is very active and talkative, a sharp contrast to his twin brother Lucas. He is also known for being mischievous and the cause of minor troubles for the townspeople.

In Mother 3
Claus first appears in the prologue, visiting his grandfather at Mt. Oriander. He loves playing with the Drago family, and spent most of his time on his visit playing outside and exploring. In Chapter 1, however, he's yet to return home from his visit because the forest ends up on fire, and there are many dangerous animals agitated. His mother is killed by one of these reconstructed animals, the Mecha-Drago, and seeks revenge after being found and rescued by the Tazmily townsfolk.

He tells only Lucas about his plan to take revenge against the Mecha-Drago for killing his mother, and steals his father's homemade knife to fight it. When Flint is put in jail for injuring a few of the villagers, Claus lets him out by concealing a nail file in an apple for him to break the lock with. Claus then heads off to the mountains, meeting the Magypsies on the way there and learning of his psychic abilities. He finds the Mecha-Drago, and gets at least severely injured in the fight. He then went missing, and none of the townsfolk know of what happened to him. Flint spends the next three years searching for him in the mountains, to no avail.

It is later revealed that while he was missing for three years, he was taken in by the Pigmasks at some point and was brainwashed and reconstructed. He became the Masked Man, commander of the army, and was Porky's loyal "robot". Porky then uses him to pull the Seven Needles, a crucial part in his plan to destroy the world. During a long battle with his brother, fighting over the final Needle, the ghost of Hinawa appears. She urges him to stop fighting, and reminds him that he's not Porky's robot, but Claus, her son. He finally recalls his former identity, and commits suicide to join his mother in the afterlife.

Trivia

 * One of Lucas's alternate outfits in Super Smash Bros. Brawl makes him resemble Claus, having red hair and wearing the same shirt and shorts.
 * Claus and Lucas's names are anagrams of each other.