Supergirl Season 4: 5 Ups & 1 Down From 'All About Eve'

4. Enter Martian Manhunter

J'onn's emotional struggles have also been a prominent theme this season. After the death of this notoriously peaceful father last year, he made a brave attempt to honour his legacy by becoming a man of peace himself - a decision that led to him stepping down as the Director of the D.E.O. However, it's been clear that he's had trouble reconciling who he is with who he wanted to be.

His multiple altercations with Manchester Black pushed him beyond his limits until he finally snapped and, in doing so, he killed his enemy using the Staff of Kolar - a violent act that made him realize that he was no man of peace.

That realization forced him to go on a journey of self-discovery in this week's outing as, in knowing who he wasn't, he wished to figure out who he actually was. The quest led to a mental conversation with his own father, which ended up pushing him harder than he had ever been pushed. In the end, he finally got the answers he was looking for.

Not only was it great to see the legendary Carl Lumbly return as M'yrnn, David Harewood gave what may just have been his finest performance yet, conveying the emotional turmoil that J'onn was in and, later, the determination with which he proclaimed who (and what) he is. Undoubtedly a fulfilling moment, he was finally aware of his potential as the Martian Manhunter and it's going to be interesting to see how he fits into the show now that he's taken the next step in his overall development.