Ōishi Sadahisa
However , their leader was murdered , and was replaced by Hōjō Ujimasa's second son Hōjō Ujiteru . 
<triplet> Hōjō Ujimasa <subj> Hōjō Ujiteru <obj> sibling <triplet> Hōjō Ujiteru <subj> Hōjō Ujimasa <obj> sibling