I recall a manga I once read, but it was far from done. The only reason I'm thinking of it now is watching the Netflix trailer for erased, but I don't think that's the one.

An isolated girl, and when the boy gets involved with her he starts to time travel and see parts of her past. As such, he beings to affect her past, and his as a consequence...

There is a school in the backdrop and I FEEL like it was semi dark. Ie one or both of the characters where "abused" to some extent in their original timeline.

Any help would be appreciate.

Yes, I run LetItGo-Scans.blogspot.ca. Where we don't just let things go.
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Welcoming suggestions for reading.
Enjoy sekirei, freezing, Shinigami-sama to 4-nin no Kanojo, school days, golden times, to love ru...
Harem-ecchi-romances

Saike Mata Shite mo?

Unfortunately no... It didn't really have powers other then the time travel(?) hook...

Yes, I run LetItGo-Scans.blogspot.ca. Where we don't just let things go.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Welcoming suggestions for reading.
Enjoy sekirei, freezing, Shinigami-sama to 4-nin no Kanojo, school days, golden times, to love ru...
Harem-ecchi-romances