Klaus

Klaus is the father of Roxy and then later revealed after having a memory spell being lifted, the husband of Morgana. He owns the Frutti Music Bar where he bartends.

Personality
Klaus is very protective about anything related to his daughter. At times, he is frustrated by her constant habit of picking up stray pets but he often lets it slide as he is just as compassionate as his daughter for animals. He befriended a white tiger cub in episode 14. He is accepting of the fact that Roxy is a fairy.

Season 4
Klaus makes his first appearence in Season Four, Epiode 4 "Love & Pet" as the owner of the Fruity Music Bar. He appears as a single father, raising his daughter Roxy as one of his employees. His bar is very popular with Andy's band performing every once in a while and fancy styles to make it lively and fun. Kind and generous he decides to hire the Specialists as his new employees thanks to their talents, looks and desperate need for a job! It also appears that he hired the Winx girls as well, but this is left un-specified due to their work with Love & Pet. He allows Musa to perform as well.

When Roxy tries to reveal to her father that she is a fairy, Klaus at first suggests she is joking; but it is revealed he is Duman in disguise. The Winx discover the real Klaus captured at the docks and confused as to what is happening. After a brief battle, he witnesses Artu becoming injured, forcing his daughter into a fairy transformation. Even more confused at this point with his daughter being a fairy, Klaus soon accepts his daughter for the way she is.

Through the rest of the season, Klaus is shown being reluctant to allowing Roxy to travel with the Winx in fear she may truly get hurt, but ends up allowing it. He is also aware of Riven's rocky relationship with Musa, and attempts to help him take his mind off of it by reminding him to do his job. Despite this, he truly cares about the Specialists like his own sons.

At the end of the Season, it is revealed that Roxy is Queen Morgana's daughter, and the latter is therefore the wife of Klaus. It is revealed the two had married long ago and had Roxy together while Morgana stayed on Earth as a human. However, when Morgana was forced to leave Gardenia to return to protect her Kingdom, she was sealed by the Wizards in Tir Nan Og, and all memories of her were wiped from the minds of all friends and family members as a result of the Wizards' negative magic, and Klaus was left to raise Roxy on his own. In the last episode, Morgana returns Klaus's memories and the two reunite; making their family complete with Roxy.

Trivia

 * Klaus is a German name. It is the abbreviation of Nikolaus, the German version of the name Nicholas, itself derived from the Greek name Nikolaos, meaning "Victory of the People", which was popularised by the Bishop of Myra in Lycia, Saint Nicholas, who is the inspiration for Father Christmas/Santa Claus.
 * Klaus is HORRIBLE at remembering people's names. He called Sky as "Smile", Brandon as "Brandi", Helia as "Tobias", Riven as "Rivet", and Nabu as "Booboo". When Timmy tells him a false name on purpose (Jimmy), Klaus actually calls him "Timmy". He does remember their real names later on.