 If you liked
Under (xGround) Grand Hotel
|
 ...then you might like
Kohitsuji Project
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Now, while their set ups are entirely different (with UGH being more "dark"), the relationship between the two guys is the same - a powerful, dark haired guy offers his protection (in exchange for companionship) to the 'weaker' guy in order to keep the other guys, who want to prey on him, away.