The sophomore installment of manga-based series "Attack on Titan" has been shelved due to setbacks in its production.

The next installment was originally slated for this year, but "Attack on Titan" Japanese director Tetsuro Araki decided to move the production to a much later date so they could have more time to improve its storyline.

According to reports, the director still wants additional plot points before proceeding with the actual production in order to ensure its faithfulness to its manga variation. Two more story arcs are needed before the manga can be adapted into a series.

In a recent interview, Araki confirmed that his team is currently facing some stumbling blocks in the development and production of "Attack on Titan" season 2.

"It's rare to adapt manga with a storyline that's impressive, so I will be extra cautious. Whether it's season 1 or season 2, I'll be mentally prepared to face the production challenges," he said.

An article published by Vine Report also says that another reason for the production delay is the generally downbeat reception faced by the two "Attack on Titan" live action films. Given the negative feedbacks received by the "Attack on Titan," the director of the second installation wants to make sure that "Attack on Titan" season 2 will be an exceptional one and will not undermine the substance of the manga series.

The second season will follow the story of the 104^th Trainees Squad's battle against the Titans. It is also reportedly going to adapt the "Clash of Clans" narrative, which involves a rise in the number of humans metamorphosing into Titans, the king being kicked out of his throne, and a revolution to be led by Erwin Smith.