Deadman Wonderland, Btooom! Recommendations
Both manga series features the theme of survival when the main male protagonist is certainly and abruptly thrown into a new environment like he has never known before.
At first, the MC seems to be timid and afraid of his new situation but as time goes on, he begins to adapt and learn new skills as well as making both allies/enemies in his quest to survive.
Both series features survival horror themes with violence, gore, and some emotional moments.
Both series also has a strange background related to the origins of their settings as well as back stories involving the main female protagonist.
Both of these amazing mangas are set in a battle-like arena in which the characters are trapped within a limited amount of space. In Btoom!, the players are stranded on an island with limited supplies, game-like powers, and bombs. Players who want to get off the island must kill others. In Deadman wonderland, prisioners are kept in a carnival for public attractions and must battle to survive. In both mangas, the theme of people vs people is present, as well as violence and gore. If you also loved the Hunger Games, these might be worth reading.