Manga 91514 Kishuku Gakkou No Juliet Userrecs

Very similar in the structure, for the start it's funny and it becomes more serious. 

The stting was quite similar, both MC and Heroine were leader of their own faction and their faction hate each other. The big difference is, while Raku and Chitoge faking relationship so their faction could live peacefully, Inudzuka and Perucia are having real relationship while keeping it secret from their faction. 

Forbidden romance, lots of action scenes, lots of fluffy moments, mature couple 

Both have a similar "secret relationship" premise and a lot of comedic shenanigans ensue to keep that relationship under wraps. Hell, they both even have the threat of "certain death" if they are found out (played for laughs, of course). Though in Onidere, most of the violence is done against the male lead, but Kishuku Gakkou no Juliet has both lovers being overtly violent towards each other when interrupted.