Blok is a native of the planet
Dryad, whose native species is
one of the few
silicon-based life forms. Dryad was destroyed
by a series of natural disasters, during which the
Legion of
Super-Heroes aided in the evacuation. A group of children from the
planet were taken at the same time by the
Dark Man and told
that the Legion was responsible for the destruction of their
planet;
Blok was among this group.
Given powers by the Dark Man, the group attacked the Legion as the
League of Super-Assassins. Blok overcame the conditioning of
the Dark Man and was captured by Polar Boy. He later helped to
defeat the Dark Man in battle. He applied for and was given
Legion membership.
Blok is incredibly strong and invulnerable, but not very
agile so he typically depends on his invulnerability to protect
him in a battle. Due to his great weight, Blok requires three
Legion Flight Rings to fly.