Hollow confirmed on discord that the legion dmk items will be in the token shop (where the current version is located)
The wording of the description could mean two things for the armor
1) two armors, one ice with darkness and earth secondaries (39. 44, 44) and one darkness with ice and wind secondaries (39. 44, 44). this of course assumes a complete copy of the existing dmk armor.
In both armors there would be an ice/darkness seeking skill, however the elecomp would be higher if the skill element matches the armor element, in this case if in the ice armor and the skill seeks to ice it should have around *1.6 elecomp, but if in the darkness armor and the skill seeks to ice it would only have about *1.45 elecomp and vice versa.
2) The wording would be a typo and we could end up with one armor with resists similar to WHEEL or the revamped Hunter armor. Resists would be 40/40 ice/darkness with elecmop around *1.55
As for the sword, it will likely be a copy of the existing doom knight blade but also have a ice/darkness toggle which makes it infinitely superior.