Despite Japan's emphasis on conformism, the mental and emotional plight of the individual is usually center stage.

• The curse of being extra-ordinary is a theme that historically extends from
  an old classic like Tetsuwan Atom (Astro Boy) to the more modern Ghost in the Shell.

• Many fight battles secretly at first, hiding their powers from the world:
  Yuusuke (Yuu Yuu Hakusho), Ushio (Ushio to Tora), and many others.

• Some fight secret inner battles...
  such as Black Jack, who sometimes cares about people in spite of himself,
  and lady Oscar has to struggle with forbidden love and her identity as a woman.

• Mostly, these characters are looking for a niche and a way of life:
  Immortal Locke wants to live in peace; Dai (Dragon Quest) wants to figure out who and what he is;
  ...and most immortals like Vampire Princess Miyu, Souko (Ao no Fuuin), Pai (3x3 Eyes)
  want desperately to be normal human beings!

Life's struggles are important, whether small or big; and perhaps it
isn't so much what one is that matters, as what one wants to be.

The quest is for finding oneself, becoming true to oneself, and finding one's place in the world.
(How's that for a universal theme?)