 If you liked
D.Gray-man
|
 ...then you might like
Strait Jacket
|
Both series are set in worlds similar to those of industrial revolution.
Both series acknowledge existence of magic as form of science.
Main protagonist is part of organisation fighting against supernatural threats.
Both worlds are quite grim/dark.
Animation is also similar.
Design of demons feels similar.
Strait jacket feels more like military anime where D-Gray Man feels more magic based.
And unfortunately Strait Jacket is only 3 episodes long so story ends with many questions unanswered, although it is quite selfcontained triplet of stories.