The Ultimate Showdown Between the Weakest From All Space and Time is a Manga/Manhwa/Manhua in (English/Raw) language, SCI-FI series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

A depressed salaryman must fight for his life in an intergalactic battle royal – but instead he teams up with his fellow weaklings to turn the tables! Hitomu is a young guy with no goals or dreams: he goes to work, comes home, sleeps, and repeats. That changes when he’s abducted by a god and forced to participate in a gladiatorial tournament to find the weakest being in all of space and time! After Hitomu loses repeatedly, he’s set against four weakling opponents to fight to the death…but he instead finds a way to escape, breaking out his fellow “losers”: a ghost boy, a slime girl, a useless robot, and a bug monster. Now fugitives on a hostile planet, the five weirdos must rely on each other. Alone they can’t do squat, but together they just might be able to survive.