That’s not clear, actually. Lewie was present on the island, but we’re not sure why Matheson rose from the dead. Some folks are just to dissatisfied and spiteful to stay down.
Matheson wasn't directly resurrected by Lewie, his death happened way before this plot had to bear any fruit. Lewie's undead was there, and his dark magic could "leak" into him to turn him into an undead, but without the conscious will behind the goal of bringing him back, his natural evil self and the negative feelings about his death's circumstances were enough to be an independent undead.
Why is Matheson not under Lewie’s control? He was also resurrected by him, no?
That’s not clear, actually. Lewie was present on the island, but we’re not sure why Matheson rose from the dead. Some folks are just to dissatisfied and spiteful to stay down.
https://www.yafgc.net/comic/0280-new-adventures-new-life-new-plot-seed/
Matheson wasn't directly resurrected by Lewie, his death happened way before this plot had to bear any fruit. Lewie's undead was there, and his dark magic could "leak" into him to turn him into an undead, but without the conscious will behind the goal of bringing him back, his natural evil self and the negative feelings about his death's circumstances were enough to be an independent undead.