Marat

Marat was a member of the secondary Thal taskforce sent to Spiridon to warn Taron's initial team about the true size of the Dalek army there. After being weakened by a trip through an ice volcano, he sacrificed himself so the Third Doctor, Rebec, Codal, and Taron could escape the oncoming Daleks. (TV: Planet of the Daleks)

_{Biography from the TARDIS Data Core article, licensed under CC-BY-SA}