No premiere date announced yet. The new PV is here. Check out the ANN article for additional information. Synopsis for the first season from AniList:
Naofumi Iwatani, an uncharismatic Otaku who spends his days on games and manga, suddenly finds himself summoned to a parallel universe! He discovers he is one of four heroes equipped with legendary weapons and tasked with saving the world from its prophesied destruction. As the Shield Hero, the weakest of the heroes, all is not as it seems. Naofumi is soon alone, penniless, and betrayed. With no one to turn to, and nowhere to run, he is left with only his shield. Now, Naofumi must rise to become the legendary Shield Hero and save the world!
It has consistently gotten worse with each season. I could barely pay attention to season 3, and I dropped it after that, which I’ll explain below:
Season 3 spoilers
At the end of season 3, with effectively no buildup, they announce that Raphtalia is actually a princess in exile. And of course she was completely unaware of this the entire time due to being a slave for her entire life. And because Naofumi gave her a specific kind of clothing to wear, that had mistakenly announced her intent to compete for the throne.
I personally find this to be extremely poor and lazy writing for what I hope is obvious reasons. Combining this with the increasingly boring seasons makes me think this series is irredeemable at this point.
Holy shit that is awful writing
Edit: and the manga since 2014 has still been going… Great.
Yeah, it’s kind of like someone (presumably the light novel author) said, “Hmm, should I just put a timeskip here until the next big bad comes along? But then the series will be shorter and I’ll lose money . . . oh, wait, orphans in these stories always turn out to have some kind of important background, right?”