A Warframe dedicated to mimicry and copying others, especially with the New War coming out. They could be a stealth frame dedicated to getting past enemies or adapting to the next big situation. Cloning Warframes, enemies, or even objects to blend into surroundings for maximum disorientation for whatever unsuspecting foe lies in wake of their wrath. And for an added punch whatever Warframe they copy, they temporarily get their abilities. (Or this can be expanded to full loadout copying, essentially making this Warframe into a specter of sorts) Their passive could be some kind of innate version of Adaption. The way I picture it in my head they could be Loki and Mirage’s (possibly Sentient inspired?) relative or trickster best friend. I think DE could have a lot of fun with this concept.