White is the purest of colors. White haired characters have an aura of strangeness and other-worldliness. Their purity isn’t associated with cuteness or moe. Cute is the color of Yellow, Pink, and Orange. White is the color of the the spiritual who lack any connect to the physical world. These colors reject everything because white is easily contaminated by any color.
White characters tend to be anti-social and lack humanity. They are often cold and devoid of compassion. The color can also be the color of nobility; they don’t need to be soiled by physical needs or work. The color can also represent innocence when used on young characters.
There are 2 famous white haired characters most anime fans will recognize: Sephiroth and Near.Sephiroth is one of the best templates for the White persona. He is a loner, yet pure in many regards. He is devoid of compassion and emotion toward humanity. He also has a noble bearing. His chief concern is the will of his mother, Jenova. His love for his mother is where his purity as a White shows. He loves his mother and follows her will as a young child would. Sephiroth rejects reality and works to mold it to his (Jenova’s) wishes.
Death Note’s Near is another good example. Near is very innocent despite being intelligent. Near doesn’t really care about humanity; he cares more about the challenge of solving a criminal case. He is calm but not entirely devoid of emotion like Sephiroth. He is very anti-social. His calmness and anti-social behavior makes him appear a bit cold.
White hair personalities are not as complex as some of the other pure-color archetypes. Authors can play with why the character acts as they do. Innocence can have a tragic backstory behind it. The lack of emotion can also be used to shield internal conflicts and insecurities.
White elements are most interesting when they are represent in blend colors like pink.
These white characteristics mainly apply to younger characters. With elder characters, white hair denotes maturity, wisdom, and dignity. Sometimes these characteristics are applied to younger characters, but this seems to be rare. Silver hair is a derivative of white. It tends to be associated with age and is more worldly than white hair persona. White haired, elderly characters are common and garner different expectations than younger characters with white hair. Youth with such hair color is rare.
Note: It is possible to have naturally white hair when young. There are photos of me as a child sporting a head of nearly white hair. I am not a blonde either. My hair darkened as I aged to the brown it is now.