Ubisoft doesn't usually doesn't make a point of parading these DLC packs on its social media account, but it posted about the so-called Yurei Bushido Pack earlier today. It also writes that the weapons and armour "once belonged to a renowned Eastern warrior".
Given that Valhalla's premium cosmetics are from all kinds of historical periods and fantastical realms, the timelines don't necessarily have to make sense for this new pack to be related to Assassin's Creed Red, which takes place in feudal Japan.
As such, could this give us an idea of what to expect from Red's artistic approach to character equipment? After all, Red is going to be an open world RPG in a similar vein to Valhalla, and the latter has been such a success that we can't see Ubisoft deviating too far from its blueprint.
It's also worth noting that 'yurei' essentially means 'ghost' in Japanese — some kind of lingering spirit. In that sense, it all sounds quite assassin-y, especially when you add 'bushido' — the general term for the moral codes that samurai tried to follow.