Complex sentence: Avenging himself on the killer, Tarzan begins an antagonistic relationship with the tribe, raiding its village for weapons and practicing cruel pranks on them; they, in turn, regard him as an evil spirit and attempt to placate him.
Split into simpler sentences: Avenging himself on the killer, Tarzan begins an antagonistic relationship with the tribe, raiding its village for weapons and practicing cruel pranks on them. They, in turn, regard him as an evil spirit and attempt to placate him.