He was a short - lived adversary for the X-Men who subsequently joined Professor X and died shortly after , making him the first member of the X-Men to die in action .
Kevin Sydney first appeared as Changeling , a mutant shapeshifter .
Kevin Sydney was a short - lived adversary for the X-Men who subsequently joined Professor X and died shortly after , making him the first member of the X-Men to die in action .
Kevin Sydney first appeared as Changeling , a mutant shapeshifter .