Maveth was an alien planet where the Inhuman Alveus was sent into exile. When he arrived, the planet had a thriving civilization, that even started to worship him as a god, but through Alveus' actions, the civilization collapsed and died, and the entire planet became a barren wasteland.
Alveus' human followers attempet to engineer his return, and periodically sent him a human sacrifice to serve as Alveus' new host body.
The sacrifices continued in modern times as Gideon Malick, leader of the cult of followers, used his wealth and connections to create the Distant Star Pathfinder project, to send astronauts to Maveth under the pretenses of studying the planet.
Will Daniels, one of the astronauts sent during the expedition, managed to avoid Alveus and survived alone on Maveth from 2001 to 2015. Was in this when S.H.I.E.L.D. scientist Jemma Simmons was accidentally transported to to Maveth and stranded there.
As Simmons and Daniels met, they were able to devise a way to find the portal back to Earth. However, Alveus ambushed them, and despite Simmons returned to Earth, Alveus killed Daniels and took possession of his body.
Malick then discovered what happened, and ordered to capture Simmons in order to force her to return to the planet and bring Alveus back. Leo Fitz offered himself to go to Maveth instead, with the only goal of bringing back Daniels while avoiding Alveus. Malick also sent a team of Hydra agents led by Grant Ward through the portal to ensure the success of the mission.
As Alveus met Fitz, still in Daniels' body, he pretended to be Daniels in order to escape with him through the portal. Alveus killed the Hydra agents while Coulson confronted and ultimately killed Ward. Fitz discovered that Daniels was actually Alveus, and seeing he could not kill him, he destroyed Daniels' body with a flare gun.
As Fitz and Coulson returned to Earth through the portal, Alveus took Ward's corpse as his new host body, and managed to return to Earth as well.
- Maveth is the Hebrew word (מוות) for "Death."