The primary aim of this paper is a description of a previously unanalyzed kind of numeral quantifiers in Japanese. While the purpose is modest, I believe that it might shed light on the Neo-Davidsonian semantic architecture (see Parsons 1990, Schein 1993 and Kratzer 1996 among others). Specifically, I will introduce Event Partitioning Quantifiers (EPQs), which have not been analyzed in literature and show that with an EPQ, agents of events and themes of events are quantified independently of both an event expressed by a lexical verb and host nominals in the subject or in the object. Based on this observation, I discuss the semantic independence of thematic roles Agent and Theme from their corresponding verb.