"Attack on Titan" season 2 is assumed to be already in the works as the hit animated series is reported to premiere sometime in April 2017. The original version premiered in 2013 and it's been a long wait for fans to see a follow-up to the titan story. Reports suggest that the second season will feature more titan shifters, putting the focus on Historia Reiss, a.k.a. Krista Lenz and Eren.
Krista works with Eren as part of the Survey Corps, the group dedicated to taking down titans. However, Krista has a hidden past and it is revealed that she actually belongs to the Reiss family, the royals who can transform themselves into a Titan. Historia or Krista is considered the illegitimate child of Rod Reiss, which could mean that she is also able to shift into a titan. Spoilers indicate that in "Attack on Titan" Season 2, Krista's true identity will be revealed, although it is unclear if the series will delve more about her past.
Meanwhile, it appears that Krista Lenz will not be the only character that could be highlighted in "Attack on Titan" Season 2. An official teaser image revealed Eren in his transformed state ready to take on the Colossus Titan. Back in season 1, Eren's father happened to inject him with a serum, which allows him to shift into a titan. Although the Survey Corps member can transform into a monstrous being, he can still retain his human intelligence and he is more inclined to help rather than destroy.
Other spoilers also suggest that "Attack on Titan" season 2 will also bring more answers to the beginnings of titans and how they ended up in the world of humans. The new season will likely feature new titans like the Armored and Colossal Titans. It's going to be about big revelations in the new season once it premieres sometime in spring.