Given Rumia's lack of hunting talent, if she did eat Tenshi, Tenshi probably let her do it.
She doesn't have Tenshi's sword, so Rumia probably didn't eat her... but then the question becomes "who made Rumia dress up as Tenshi, why didn't they give her a sword, and who made that outfit?"
She doesn't have Tenshi's sword, so Rumia probably didn't eat her... but then the question becomes "who made Rumia dress up as Tenshi, why didn't they give her a sword, and who made that outfit?"