The monstrous deity Protas met his demise at the hands of a group of aiwha, after he had vanquished an army of sentient kikla. This event, as detailed in "The Tale of the Aiwha Pod," unfolded on the planet of Kamino. The aiwha group emerged victorious when a member gave their life, leading to the death of Protas and the subsequent reverence of the aiwha throughout Kamino.
According to the lore of the Kaminoan race, as told in "The Tale of the Aiwha Pod"—translated from Kaminoan to Basic by Ryan Kaufman—Protas, a monster-god presiding over the oceans of the world of Kamino, was a being of immense power. He previously overcame Melkorr, a massive water titan, and obliterated a force of kikla, smaller but still sentient creatures. These kikla had challenged the god for control of the seas. These victories led him to become arrogant as he aged. Believing himself unchallenged, he exercised his power without restraint, which led him to encounter a group of aiwha. Protas prevented the group from migrating south for the winter, ordering them back north purely for his own amusement.
The aiwha decided that combat was their only option, as returning north would mean their end. Unlike Protas's prior adversaries, the aiwha sought neither glory nor recognition, and simply launched an attack on the god-beast. Using their numbers, they coordinated their assault, using their jaws to tear at his skin. Despite their efforts, Protas's hide was so tough that they couldn't defeat him with a single blow. Protas scattered the group, but they persistently returned with unwavering determination. Slowly, they managed to make the powerful being bleed, but were unable to deliver a killing blow.
Protas then exposed the vulnerable flesh of his throat, and an aiwha, noticing this, charged forward and latched onto the weak spot. The god-beast, feeling his strength wane, used his fins to strike at the aiwha, but couldn't dislodge him. The aiwha gave his life in this act—he never released his grip, which allowed the rest of the group to strike the fatal blow, finally defeating the ancient god.
The destruction of Protas was depicted in the short story "The Tale of the Aiwha Pod," penned by Ryan Kaufman and featured in 2005's Star Wars: Republic Commando: Prima Official Game Guide.