The manager of the estate who Jesus talks about in Luke 12:42-48, who does he represent?

Jesus is teaching at the time He makes this analogy. He says, “Who then is the faithful and wise manager, whom the master puts in charge of his servants to give them their food allowance at the proper time? It will be good for that servant whom the master finds doing so when he returns. I tell you the truth, he will put him in charge of all his possessions. But suppose the servant says to himself, ‘My master is taking a long time in coming,’ and he then begins to beat the menservants and maidservants and to eat and drink and get drunk. The master of that servant will come on a day when he does not expect him and at an hour he is not aware of. He will cut him to pieces and assign him a place with the unbelievers. That servant who knows his master’s will and does not get ready or does not do what his master wants will be beaten with many blows. But the one who does not know and does things deserving punishment will be beaten with few blows. From everyone who has been given much, much will be demanded; and from the one who has been entrusted with much, much more will be asked—Jesus Christ, Luke 12:42-48. Now, in the context of the moment, Jesus has been telling the disciples, Be dressed ready for service and keep your lamps burning, like men waiting for their master to return from a wedding banquet, so that when he comes and knocks they can immediately open the door for him. It will be good for those servants whose master finds them watching when he comes. I tell you the truth, he will dress himself to serve, will have them recline at the table and will come and wait on them. It will be good for those servants whose master finds them ready, even if he comes in the second or third watch of the night. But understand this: If the owner of the house had known at what hour the thief was coming, he would not have let his house be broken into. You also must be ready, because the Son of Man will come at an hour when you do not expect him”—Jesus Christ, Luke 12:35-40. The greatest moment of expectation we have to look forward to is the Rapture, when Jesus will in an instant call His entire church (all true believers) home to heaven to be with Him. The “faithful and wise manager” in this analogy is a reference to a true believer in Christ, who is doing what Jesus has given Him to do. When Christ comes, He finds that servant faithfully doing what he or she has been given to do. The drunken servant who beats the other servants is a picture of nonbelievers—doing what they want, totally oblivious to the comings of the Master. As Christians, even as we live out our lives, we should be aware and alert for our Master’s coming. As Paul said so well, Now, brothers, about times and dates we do not need to write to you, for you know very well that the day of the Lord will come like a thief in the night. While people are saying, “Peace and safety,” destruction will come on them suddenly, as labor pains on a pregnant woman, and they will not escape. But you, brothers, are not in darkness so that this day should surprise you like a thief. You are all sons of the light and sons of the day. We do not belong to the night or to the darkness. So then, let us not be like others, who are asleep, but let us be alert and self-controlled—Paul, I Thessalonians 5:1-6.
A couple of other things to note: (1) The faithful servant was commended for both being watchful and, simultaneously, for continuing to work. Jesus may come at any time. While that could be imminent, we need to continue the work of the Kingdom. (2) We are accountable for how much we know, and people outside the Kingdom will be accountable for what they have heard. While the Bible clearly teaches that [t]he wrath of God is being revealed from heaven against all the godlessness and wickedness of men who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse—Paul, Romans 1:18-20, eternal punishment will be leveled based on what a person genuinely knew (judged perfectly by God) and what they did with it. Obviously in the context of this story, the unfaithful servant should have known better—and was judged by a higher standard due to his willful wrongdoing despite his awareness of what was right.