Sword Art Online is still pretty popular in Japan right now despite the anime ending a couple of months back, and Nexon Japan found it appropriate to recently add content from the novel-turn-anime into 1 of its oldest online game, TalesWeaver. This event will only last until the end of July.
As you can expect, there are tons of costumes, character change items (into SAO characters) and titles from either both cash shop, clearing the new dungeon or exchanging medals for them. In Sword Art Online style, the new tower dungeon will see 4 ascending sections, each with 3 levels.
