Tallon IV is the setting of Metroid Prime
. It was the site of an ancient Chozo
settlement before a Leviathan crashed onto the planet and began corrupting it, about 50 years prior to the events of Metroid Prime. The Chozo on Tallon IV either died out from Phazon
Madness or became insane specters who attacked any intruders to their territory. Before they died out, the Chozo built a temple around the Leviathan's impact crater in an effort to contain the corruption and the 'Worm' that resided inside. The Chozo completed the Artifact Temple and sealed the Worm, but it was too late to save themselves and the planet from the corruptive influence of Phazon.
The Space Pirates
, fleeing from their defeat on Zebes
at the hand of Samus Aran
, detected immense power readings from the planet and sent teams to investigate, discovering Phazon and beginning to test on it. Through mining the substance, they delved into the impact crater and awakened the 'Worm', a Metroid mutated by the power of Phazon, which they called the Metroid Prime
. Samus arrived on the planet shortly afterward, disrupting the Space Pirate operations and defeating the Metroid Prime.
Tallon IV was classified as an 'ecological paradise' by the Galactic Federation before the Leviathan hit the planet and started to erode it. As such, its landscape and wildlife are extremely diverse, consisting of lush jungles, frozen mountains
, and an underground series of lava-filled caverns. The Space Pirates also built a base there to mine Phazon, and the remains of ancient Chozo ruins
make up a large area that Samus explores.