He became revenge-seeking, determined to punish those who had wronged him.

revenge-seeking 是由名词 revenge（报复）和现在分词 seeking（寻求）组成的复合形容词。revenge 指"报复、复仇"，seeking 来自动词 seek（寻求），表示"正在寻找的"。 revenge-seeking 合起来表示"寻求报复的"，形容一个人怀着强烈的报复心理，想要对伤害过自己的人进行报复。