In the ultimate sense, Christ-Jehovah is the keeper of the gate and the judge of all men and women (2 Nephi 9:41; John 5:22). In addition, priesthood leaders- as exemplified by the Twelve who will judge the whole house of Israel- stand as judges of those persons who lived and labored during their ministry and under their direction (see Matthew 19:28; 1 Nephi 12:9; Mormon 3:18-19; D&C 29:12; Bruce R. McConkie, Millennial Messiah, p. 520).
In one sense, however, each of us becomes his or her own judge, since we make those decisions which determine the kind of life we will live here, and thus where and with whom we will dwell hereafter. Truly, as Samuel warned, “whosoever perisheth, perisheth unto himself; and whosoever doeth iniquity, doeth it unto himself; for behold, ye are free; ye are permitted to act for yourselves” (Helaman 14:30).
Because in that day of judgment the works of man will be evident, because there will be nothing hidden, and because we will have a perfect knowledge of our uncleanness as well as of our happiness, it will not be necessary for a designated person to consider our case and adjudicate our life. We will be what we have become. Our natures will have been prepared for that kingdom of glory which is most appropriate to the decisions we have made in mortality.