The Bimanese particle kai occurs both as an instrumental preposition preceding a noun phrase and within the verb complex, where it performs a variety of syntactic functions that fall into two main groups: valency-increasing and nominalization. However, in discourse, a substantial number of instances have no clear syntactic function, and appear to be performing a discourse function instead. In this paper, based on our examination of a corpus of narratives and conversational data, we outline the main syntactic functions of kai, and investigate its discourse distribution. Valency increase may involve the licensing of an additional applicative object with either a one- or two-argument verb, or more rarely the creation of a one-argument verb from a nonverbal base. Nominalizations are of two types, one producing locative nouns, and the other nominalized clauses. Discourse kai is found with both transitive and intransitive verbs, with no increase in valency.