 If you liked
Darker than Black: Ryuusei no Gemini
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 ...then you might like
Zettai Karen Children: The Unlimited - Hyoubu Kyousuke
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The feeling of the series is very similiar : "Dark". (Also to the main series "Darker than Black" is very similiar to The unlimited) And of course both animes are about special powers, like ESP.
The main characters are neither good nor bad people - kinda in the "gray" zone, thats what makes the character developement interesting.
And while Hyobu tries his best to save Yuugiri, and fulfill her wishes,
Hei travels with Suou on his journey and is kinda a mentor to her.