Ket Rosteen, known by his title as the True Voice of the Startree, is a Templar charged with the care of the Startree Biosphere.
SPOILER ALERT! The section(s) below are MAJOR SPOILERS.
He also captained the treeship known as Sequoia Sempervirens in carrying Martin Silenus, Raul Endymion and company to Silenus' final resting place on Old Earth.