Ao no Exorcist, Code:Breaker Recommendations
Rei looks a little bit like Rin and the blue flames.
They both have the action, Shounen and Supernatrual genres.
Rei and Rin have the same seiyuu.
>Both revolves protagonist using blue flame.
>The flames are powers of evil, Satan Flame for Ao no Exorcist
>Protagonist has the same seiyuu, Rin and Rei
the main character, rei ogami, has the same power as rin okumura [also the initials, RO and the voice actor], although the plot differs a lot, the feel of the anime is same.
the genre also aligns with each other being supernatural, shounen and action.
Both of the main characters use blue flames as their main weapon—not to mention a katana as well.