Thank you in advance!

Wolf Guy - Ookami no Monshou
[url=https://www.mangaupdates.com/series.html?id=40128]

there is Kurenai Ouji, what your describing is not the main plot of this manga but he does keep his true nature hidden from the rest of the school and the family that takes him in.

Noblesse maybe, he does hide what he is from the students but it almost never shows him in school after the first part of the story.

Orange Marmalade - this one probably fits the best, its about a vampire girl that has to hide her identity from her classmates so that she does not get bullied.

[img]http://24.media.tumblr.com/3b280fafb72cad0f718be64368e64ca7/tumblr_myylzmuiY41rw3pzao4_250.gif[/img]
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