A member of the Legion of Super-Heroes
Troy Stewart of Earth is the real name of the hero Tyroc.
Troy was born on the island of Marzal which, though on Earth,
exists in another dimension and only appears occasionally on Earth.
Troy was born with abilities based on his voice, which he used as
the protector of Marzal.
When Marzal shifted into Earth's dimension,
Troy or Tyroc as he was called met and helped the Legion of Super-Heroes.
Tyroc was a member for a short while, but returned to Marzal when
it shifted dimensions again.
Now for a bit of unasked commentary: The Tyroc character was a attempt to
make the Legion of Super-Heroes
intergrated. A noble idea, but
unfortunately, the character was extremely weak and so the whole
idea comes off as a bad case of tokenism.