The "Imposter" is one of the two main roles of the multi-player game Among Us. Resembling like every regular Crewmate, the imposters are hostile aliens that integrate themselves in the group, sabotaging their efforts, killing their members and throwing off suspicion to others. However, they must be careful enough to avoid suspicion or they will be dealt with by the Crewmates. They first appear in Randomized Hunger Games III.
There are numerous custom events that reference to the Imposter's kills and behavior, although they are not counted as such since tributes are the ones that perform them to each other.
Thus, any kill committed by a tribute that is labeled as an Imposter in-season does not accumulate to their overall kills.