Supergirl deals with the fallout of the Daxamite invasion, a new shady businessman, religion, magic, and time travel.
- Aborted Arc:
- Alex and Maggie's engagement was short-lived because Floriana Lima wanted to leave the show after Season 2, so they broke up because Alex wanted kids but Maggie didn't.
- James was meant to have a bigger role as Guardian in this season, but so far he only suited up in "For Good".
- "For Good" was supposed to start a plot of Lena descending into evil. This, along with all the storylines devised by Andrew Kreisberg, were shelved after he was fired.
- Dumbass No More: After seven years in the future leading a team of heroes, Mon-El comes back calm, wise, and even more experienced than Kara. Several times Kara is shocked that the advice he is giving her is actually good.
- Superpowered Evil Side: All the Worldkillers have a human personality that is mostly unaware of what they do when they have superpowers.
- Transhuman: The Worldkillers are trans-Kryptonians made with science and magic. Reign is by far the most powerful of them.