 If you liked
Rainbow: Nisha Rokubou no Shichinin
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 ...then you might like
Yakusoku no Neverland
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Both series includes being locked in a certain place and the characters attempts to escape from there. Though in Rainbow it doesn't include supernatural beings like Demons.
Both shows have hard-hitting drama and a story about companionship blossoming in the face of corrupt authority and the hardships such bonds can bring. Rainbow:Nisha Rokubou no Shichinin is a more conventional character drama with a thriller undertone and some historical elements whereas Yakusoku no Neverland is a psychological-horror thriller through and through with more "targeted" drama and supporting mystery elements. If you grew attached to the characters in Neverland I suspect Rainbow will be right up your alley and vice versa if you enjoyed the beginning of Rainbow the most Neverland will not disappoint you.