In this paper, we presents a unified theory of the pre-final ending {-deo-} in Korean. In particular, we propose that the {-deo-} in Korean functions as a grammatical morpheme triggering the change of a speaker's empathy. The {-deo-} has been usually regraded as either a retrospective marker or a reported (i.e. indirect) marker among Korean linguists. By introducing a new concept of ‘empathy,’ however, we attempt to explain the information structure of the {-deora} construction in a uniform way. Empathy refers to a speaker’s individual perception or experience about the given event, and it consists of three major categories; that is, the place where the event happened, the time when the event took place, and the speaker’s emotional experience about the given event. In the hierarchical (or linear) structure of a sentence, the {-deo-} tier is used to show the change or shift of a speaker’s empathy from utterance point(including time, space, attitude) to reference point. In other words, in the {-deo-} level of structure, a speaker’s empathy returns to the specific point of the past event, which was once neutral to the speaker’s mind.
As discourse indicator denoting the shift of a speaker’s empathy, the {-deo-} leads a hearer to be sympathized with the speaker’s instantaneous recognition about the given event. The concept of empathy or the shift of empathy can account for the previously observed complicated semantic and discourse effects in an integrated way. In addition, the change of a speaker’s empathy can be attested in other Korean sentences containing reflexive pronoun {jagi} and discourse markers {-do}, {-man}, and {-neun}. Accordingly, the analysis of the {-deo-} in Korean can be satisfactorily accomplished in the information structure level, but not in the morpho-syntactic level.