Sword Art Online's third season has been the most ambitious in the series thus far as it's in the midst of adapting one of the longest arcs of the original light novel series to date. After wrapping up the first half of the Alicization story earlier this year, Sword Art Online has finally returned with War of Underworld. The first episode of the series' midseason premiere has officially kicked off the "Alicization Invading" phase of the story, but how long will Season 3B run for? New home video listings on the series' official website confirmed that it will last for 23 episodes overall.
Official listings for the series' home video releases confirmed that Sword Art Online: Alicization - War of Underworld will last for 23 episodes, and is scheduled to have eight home video releases in Japan overall. The second half of Season 3 will be split into two cours, and this is reflected in the home video releases as well.
The first half of the home video releases will be shipping from this December to March 2020, with the second half beginning in June through September 2020. Although there currently is no confirmation that this will be the schedule of the two cours, but there have been reports that this War of Underworld would be taking a brief break before it's all said and done.
If you wanted to jump back into the series, you can currently find Sword Art Online: Alicization - War of Underworld streaming on Crunchyroll, Funimation, HIDIVE, and Hulu. War of Underworld is described as such, "Kirito, Eugeo, and Alice. Six months have passed since the two disciples and an Integrity Knight brought down the pontifex, Administrator. With the fighting over, Alice has been living in her hometown of Rulid Village. Beside her is Kirito, who has not only lost his arm and soul, but also his dear friend.
As Alice devotes herself to looking after Kirito, she too has lost the will to fight she once had as a knight. “Tell me, Kirito… What should I do?” Nevertheless, the time for the final stress test – one which will engulf the entire Underworld with tragedy – draws relentlessly closer. Meanwhile, in the deepest areas of the Dark Territory, the Dark God Vecta has resurrected, as if to have waited for this very moment. Leading an army of dark forces, they begin their invasion into the human empire in hopes of attaining the Priestess of Light.
The human empire force led by the Integrity Knight Bercouli prepares for a war of an unimaginable scale against the army of the Dark Territory. Even then, Alice is nowhere to be seen, nor the two heroes that saved the realm… The curtain rises on the final chapter of the SAO series’ longest and most glorious battle – the Alicization arc."