Icebrood Norn
Because they’re not oakhearts, though they do use the same model. You can clearly see skin, bone, muscle, and clothing under parts of the ice. Though not in your attachment due to the small size.
Icebrood go through various stages – not “evolve” like you compare with pokemon – at first they’re mostly flesh with a bit of ice. These would be your Icebrood Berserker and whatnot. Then over time their veins solidify and skin slowly turn to ice. These would be the larger Icebrood Norn, the Icebrood Goliaths, and Icebrood Colossi (the last being, quite literally, a skeleton encased in ice).
Stop treating GW2 as a single story. Each Season and expansion should be their own story.
From how I understand it, they warp and change over time. I believe the Icebrood Norn like the one you posted would be one that’s been corrupted to a point that it’s completely warped into what we see here, slowly becoming monsters.