As Kirito's real world body is recovering from a near fatal attack in Sword Art Online: Alicization, his soul has been living in a new virtual world without any memory of how he got there. Now that he's chosen the path of swordsman in this world, he needed a new sword as well.
After one year of training in a special swordsmanship academy, Kirito has acquired a new sword that sort of resembles his older swords, but made with a much denser material.
While Kirito has yet to give his new sword a name, there's an implication that it is a powerful weapon. Not only did the Blacksmith fashion the blade out of a material gained from an impossible to cut tree, he called it a "monster" due to how heavy it became as a sword.
Giving it to Kirito for free when he's able to swing his sword, the rules of this new virtual world imply that Kirito has gotten to a high enough "Control" level to properly wield the sword. Fans aren't given any stats for the new weapon, but Kirito is able to use his five-hit strike sword skill with this new blade. It seems made for him as well as when he tried using the other important sword of the series, Blue Rose (which now belongs to Eugeo), he was not able to activate such a skill.
While this is merely a taste of Kirito's swordsmanship in this world, fans will get more of a showing for it soon as Kirito's wrangled into a deadly sword duel by the end of the episode. We'll see what Kirito can do with this new weapon for sure.
Sword Art Online: Alicization can currently be found streaming on Crunchyroll, Funimation, and Hulu. The series is officially described as such:
"Where... am I...?” Before he knows it, Kirito has made a full-dive into an epic, fantasy-like virtual world. With only a murky recollection of what happened right before he logged in, he starts to wander around, searching for clues. He comes upon an enormous, pitch dark tree (the Gigas Cedar), where he encounters a boy. “My name is Eugeo. Nice to meet you, Kirito.” Although he is supposedly a resident of the virtual world - an NPC - the boy shows the same array of emotions as any human being.
As Kirito bonds with Eugeo, he continues to search for a way to log out of this world. Meanwhile, he remembers a certain memory deep down within him. He remembers racing through the mountains with Eugeo as a child... A memory that he should not have in the first place... And in this memory, he sees someone other than Eugeo, a young blond girl. Her name is Alice. And it is a name that must never be forgotten...”