It's complementary to Kibana, I would say. Dejavu gives the raw data view as well as an ability to add/update data along with mappings. It also comes with an importer view where you can add JSON / CSV files to directly import into ES. Doing this otherwise currently is a major PITA.

Kibana is more for dashboarding and visualization, Dejavu gives you control of the raw data views and indexing operations.