Trion (species)

The Trion are a race of Near-humanss from the planet of Trion.

Physical charateristics

They look identical to Humans and can survive in similar conditions.

Since the nurse at Turlough's school had no problem when examining Turlough, that would imply that Trions have similar, if not identical, internal structure to Humans. (DW: Mawdryn Undead) Based on Turlough's comments, he may be older then he looks, implying a different aging rate. (DW: Terminus)

History

Sometime before Turlough's time, Trion suffered an invasion with the Tractators, an experience so horrific that in generations to come, ancestral memory would trigger at the sight of one, sometimes, in the case of Turlough, causing abject panic and fear. (DW: Frontios).

The Trions are a reasonably advanced species, having space-faring capabilities and energy weapons. One Trion seemed completely unfazed by the fact that the Doctor's TARDIS had a transcendentally dimensional interior. (DW: Planet of Fire) Turlough had familarity with transmats. (DW: Mawdryn Undead)

The Trions had colonies and representatives on many planets, including Earth, where Turlough had exile (DW: Mawdryn Undead), Sarn, Darvey and Verdon). Despite this, many of these colonies were poorly maintained or forgotten, such as in the case of Sarn. (DW: Planet of Fire)

Following a civil war on Trion, the losing side and their families were sent to various other planets. These political criminals were marked with the Misos triangle and were watched over by the Custodians. This practice was later abandoned and the prisoners were allowed back to their original home. (DW: Planet of Fire)