The English-language subreddit is rife with speculation; the current consensus is that it’s a Warrior archetype coming in June; according to datamining claims, it’s destined for the Jin and Gon races (alas, your Lyn won’t be running around with a sword thrice her size). Interestingly, while the site teases only the Warrior, the datamined files seem to suggest an Archer coming for the Jin and Lyn. The biggest point of contention seems to be that June date, so maybe consider that part rumor, and in any case, since we don’t know when it might drop for the west, it probably doesn’t matter much yet.
Source: Official site, Reddit. Thanks, Raijin!
