Sifelius was a famous composer, who was very talented with great passion until the death of his beloved wife Irenja. The Winx helped him see his wife again and is no longer heartbroken. Sifelius has only appeared in the comic series.
While his age was never stated, it can be assumed that he is around his forties to sixties determined by his appearance and friendship with Solimante.
Sifelius has tan colored hair, with graying streaks that are past shoulder length. He has a crow's nest style, his hair is thick and curls upwards at the ends. When he was young, his hair color was much darker tan color, lacked the graying streaks and was pulled back by a red bow in a low ponytail. He has tan colored eyes and a slightly tan complexion. Before Musa helped him, his hair was unkempt and had stubs.
He has two civilian attires.
Before grooming himself to see his wife once more. He wore an orange and yellow robe which has a rip on the right shoulder, with a white t-shirt underneath. He had blue and light blue stripped pants, and dark gray and white loafers.
After grooming, his hair is neat and tidy, and he had also shaved. He then wears a composer's attire, which is a velvet red white tie style suit, underneath is a pink dress shirt with a velvet red bow, punch colored vest, a purple (or yellow) rose on his left breast, light blue and blue (or just blue) striped dress pants, and dark and white loafers.
In the past, Sifelius was a talented composer and loved music, this was especially true when Irenja, the love of his life, joined him in his concerts, bringing out the best of him. Her death however, affected him severely and all the love he had for music turned into painful memories.
Before meeting Musa and the Winx, Sifelius was shrouded in his depression after the death of his wife. He refused contact with the outside world, locking himself up in his home, and would not speak to anyone, not even Solimante. Over the years, he grew grumpy and cranky, quick to anger, easily forcing anyone out who trespassed on his personal life. His, as he would describe it, "evil and old" appearance and personality was a way conceal his pain.
But, Musa did not give up even after he shouted at her and told her to scram. He realized he had gone to far and called her back, and spoke to her. It was awkward at first, considering it has been years since his last conversation with someone (and the fact that Musa was still a little angry) and eventually felt that he could trust Musa. He then spoke about his past. In a sense, it allowed him to relieve some of his pain and his only wish was to see his wife again.
Determined to help him, Musa and her friends found a way to allow Sifelius to see his wife again. When Musa informed him that it is possible, he could not contain his joy but was frantic about it because the mansion and himself was a mess. He then cleaned himself up, and returned to his former, lively and happy self. After seeing his wife again, he completely regained his former self, as he was very social, smiled a lot, and showed many emotions aside from anger.
After becoming very distraught as a result of Irenja's death, it can be assumed that he was loving and faithful to the person he loved.