Love me if you must. I've been worshipped before, so I can stand your love. Treat this as an apology if you ever hear it. A false god, begging forgiveness from a species long overdue for extinction. Not that I expect you to become extinct. Some of you will outlast even the death of this universe. You will be greeted as gods and damned as devils and you will do to them what I have done to you and they will love you as you love me. And in all that time, not one in a million will know what it is that you have done to them.

Please. Before it happens. Return home and undo what I have done.

'Return home.' I remember when my father stopped living. He had spent most of his life dosing himself with a substance called tobacco. Just before we gave up and let them take him to hospital, he said that he had done everything he had ever wanted to do. He meant that he had seen lots of cricket matches and been married and seen his children grow up and even seen one tiny granddaughter. Just after he died, I went to the park where he used to play with me when I was a child. I remembered that there was an enormous statue of a lion in the park: twice as big as me. He used to pick me up and let me sit on it. It was a thing you did with children. Going and looking at the statue seemed like a better way of commemorating him than going to see the place where they had put the burned remains of his body. It seemed important to do something to show that you remembered a dead person. When I found the lion, it turned out to be a disappointing little ornament made out of brass, perhaps: now green with age. I couldn't shake the impression that the lion had shrunk, whereas I knew that it was me who had grown. It's that giant lion that I hold in my memory, now, not the small one that I know to be more real.

Since then, of course, I have seen a lion that really was twice as big as me. He begged me to be his ambassador and played me savage, rasping music on a wind instrument carved out of stone. Was he one of the ones I corrupted with my gift? It is hard to remember.

Sometimes I think that all this has changed my mind as much as it has changed my body. At other times, the memories slip away and I am what I have always been. A human, a teacher of. . .one of the sciences, I foget which, a graduate of - some university. The son of. . . Of a smiling man with half rimmed glasses and red hair, who brought me up in a town. In a house. A house with a blue door, with dahlias growing in the garden.

Eventually, like him, I decided that I had done all that I had ever wanted to do. So I returned home. I had promised that I would do so and I wanted to keep my appointment.

But the planet's long whimper seemed to have ended. I wandered for centuries through cold deserts in continents that I no longer knew. I never doubted that my fellow was still there, somewhere, waiting for me. But I despaired of finding anyone but him. Occasionally, I came across a valley in which a little moss and some shrubs still grew. Sometimes, the valley would be full of the bones of small animals, that had migrated across the deserts and fed in the valley until all the plants were gone and then died. Sometimes, smaller creatures gnawed on their bones. An archaeologist, perhaps, could have searched through the dust and found a piece of plastic, a particle of rust and said: 'Proof. People lived here once'.

I started to follow the herd animals; across the deserts; into the hills, from valley to valley. And one day, on one continent, the creatures led me across the brow of a hill; and I saw, in one of the fertile valleys, that the mosses and shrubs had been cultivated; and the animals husbanded and there was a village of tiny huts built around the ruin of an old metal building. Coming out of the huts and pointing up the hill, pointing at me, with joy, fear and disbelief, were people. Human beings, like me.

Not like me.

I walked past their farms and dwellings, straight to the ruined building in the middle of the settlement. Its walls were green with age; its roof had fallen in. Centuries ago, some of the holes might have been windows and doors.

Some of the people came out of their huts to see me. Some of them went into their huts, to hide from me. At the entrance to the ruined building, an old man, dressed in robes, greeted me.

'I am Thaddeus', he said. Fear, hope and confusion were mixed in his voice. Some of you know what it is like. The machines in our blood change our appearance as they remake our bodies. I've been likened to the dead. I've been told I look like a machine and compared with a walking statue. 'Where have you come from, stranger? We are the only people in this land, I am sure of that.'

'I have been wandering in this land and in many others' I said 'For a long time. But I have not seen anyone else like you. But there are so few of you here. Surely there must have been more, at some time?'

'There were', he said 'But most of them left for another village. It was called 'Space' I think. I expect some of them are still there. But I am old and do not like long rides.'

'Perhaps I come from that village.'

'Perhaps you do,' he said, doubtfully. He beckoned to me to go into the ancient structure and I did so. He took me through another opening, into a room where the walls and ceiling were intact. There was a raised platform with a table on it and a book and a cup on the table. The room was dimly lit. Thaddeus made some sort of gesture of respect towards the table, touching his shoulders and his forehead and bowing.

'If you do come from the other village,' he continued, 'Then tell me about it. How many of you survive? I don't mind telling you that there are very few of us and there has been plague here. I sometimes think that the long story may be ending. But if there are others -- we could share our possessions, we could inter-marry. . .'

'I am sorry,' I said, 'If there is another community on this planet, then I have not seen it. And I have been looking for -- a long time. I do have a friend, somewhere in this world. I would like to find him.''

A younger man brought in a wooden dish with some grey bread and some bitter meat on it and two cups of water. Thaddeus ate very little of it. I, of course, ate nothing.

'How long have you been here?' I asked.

'Since I was a boy.'

'I mean, your people.'

He thought. 'A good number of years. Since my grandfather's time. Since the others left.'

'But you didn't go with them?'

'Grandfather wouldn't. He said that he had made a promise and would wait it out. He said one family would be faithful, if all the rest deserted.'

I smiled. 'A very large family,' I said.

He shrugged. 'Well, that's the story. Perhaps he was really a great-grandfather. Or a great-great grandfather. Or -- perhaps he just had an awful lot of kids.' He started to laugh and the laugh turned into a cough and he sunk into a stone chair and coughed blood onto his robe. As the coughing stopped, his voice sounded terribly hoarse. 'Thirty years ago', he said. 'I ordered the death of a man. He had killed another in a quarrel. The law says that blood must pay for blood. It was the first crime that any of us could remember. I think he just had the devil in him. He ran mad in the hours before we did it to him. Begging us to do it now and have done with and cursing us for doing it at all and swearing that the other man had started the quarrel. Now the Pontiff before me, he died of the plague and the physician told him he had only an hour or so to live. So he called the community together and he said good-bye to us all and we all prayed and when he was gone, we cried and then we sang a holy song. Whereas we. . .' he gestured towards the building 'We are just carrying on as if everything was normal, as if we weren't all going to die out in a generation, as if we were not going to be forgotten. Don't you think our way is best?'

'It may be.'

'Death does not frighten me. You young people do not understand that. But to be among the last and then to miss him by a single generation!'

All of my crimes have been precipitated by pity. Believe that of me, if you believe nothing else. I took the broach that Thaddeus was wearing on his robe and stabbed my hand with it. My once human blood, crawling with microscopic machines, invisible, still multiplying, dripped along my wrist and onto my sleeve. Almost immediately, the cut closed and healed.

'There is no need for you to die.' I said. 'I have shared my gift with most of the universe. I will happily share it with you.'

He looked at me for almost a whole minute. 'Let now your servant depart in peace. . .' he whispered. 'Oh, you must think me a very foolish old man.' he said, 'But I didn't recognise you.'

I should have said something, of course. But the relief in the old man's eyes, that look of hope, as if his life had not been wasted. He was kneeling by his holy table, weeping and mumbling, half at me, half at the book. I tried to start: to say 'I am sorry, old man, but you are mistaken', but I could not bring myself to do it.

I played my role and I gave him what I still thought was a gift. It hurts, at first, when the machines breed inside you and start to remake every part of you, from the inside. I heard him cry out; and then, slowly, he stood up.

'May I go outside and bring the others?'

'If that is what you want.'

'Can I share what you have given me with them?'

'If that is also what you want.'

He gestured through the door 'The world. Will it end?'

'Not yet' I said 'Perhaps soon.'

He looked slightly disappointed. Then he made the same gesture of respect that he had made to the table with the book on it and left me alone in the room.

He came back with ten other men, robed, as he was. Their talking stopped as they entered the room. They bowed to me and looked at Thaddeus, expectantly. Fortunately, he spoke for me.

'His blood has mingled with mine. Death cannot touch me. And he told me that I can share this gift with whomsoever I chose.'

I suppose that was, more or less, what I had told him.

He had brought a knife with him. He handed it to me. I was reluctant to continue to play this role that he was marking out for me, but, short of telling him that it was all some mistake, I could not see how. And besides, in a day or two, his blood would be as potent as mine; and once that happened, if he wanted to share the gift with the others, I would not be able to stop him. I have seen whole civilisations become deathless in the space of a year. He handed me an ornate knife that he had brought with him. I cut myself. He collected some blood in the metal cup and held it reverently for a few seconds and murmured something that sounded like a spell. He handed it to one of the ten men who he had brought in. The man cut himself and let some of the blood into his own veins. He came back to me. I squeezed another drop into his cup. He went to the second man, whose face was a mixture of disgust and rapture, as he saw the man on his left, becoming younger as he looked. The ritual continued; a third man, a fourth, a fifth.

'Stop this!'

A new figure, robed like the others, stood at the door to the room. He held a religious symbol before him and, was mouthing something under his breath, as if casting a spell. I had no doubt that it was directed at me.

'Nathaniel, do not do this...'

'I will do this. In the name of all that we ever revered, I shall do it!

He walked forward, still holding his symbol before him. He pushed through the little circle of men and knocked the cup and the knife from Thaddeus's hand. As he saw that there was blood in the cup, he winced in disgust.

'A week ago; an hour ago; you were men of god! Now what are you? Leeches? Vampires?'

He turned to me. I don't think that he saw Thaddeus stooping. 'What are you? God? Christ? The very devil, come to tempt us again at the end as you did at the beginning? With the same temptation? Oh you are very clever, but we were warned against you; that you would come in his name, claiming to be him. Standing in our temple -- the abomination of desolation! Whore of Babylon, drunk on the blood of the saint?'

He never finished his condemnation of me. He crumpled to the ground, his robe reddened with an ugly wound. Thaddeus could not bare to hear his new god denounced and he was holding his ceremonial knife.

'Thaddeus. What have you done?'

'Justly punished the Son of Iniquity, my Lord. Someone was bound to be lost, so that the scripture might be fulfilled. I never thought it would be Nathaniel.'

This man just killed someone who was once his friend, I thought. This is the sort of man who becomes and inquisitor, a holy warrior. It is such a man to whom I have given a new cause. It is such a man who I have made immortal.

'I ask you all to leave,' I said. 'I will summons you if I want to see you again.'

The others left. I beckoned to Thaddeus. He remained for a moment, still holding his bloody knife.

'Every word was true.' I said 'I am no god, nor devil, nor anything else. Remember that you tried to kill an innocent. Remember that you embraced a false god. Live with that, now that you are like me.'

He left me alone in the sanctuary with wounded Nathaniel. It was an ugly wound. But the machines in my blood could still do their work. Rebuilding, perfecting, regenerating.

The dying man looked at me, pityingly. 'They thought you were God.'

'I am a man.' I said. 'Deathless and much travelled. But still a man. And I can share my deathlessness with you.'

'Then you are the devil.' he said. 'Leave me alone.'

'No' I said 'You don't understand. I want to save your life.'

'I understand very clearly', he said, 'Leave me alone'.

I ignored him and picked up the knife. With a terrible forcefulness he gasped. 'I forbid it.' Then, in a puny whisper, but less angry. 'I have done all that I wanted to do. And now the Lord is calling me home.'

'You want to die?'

'I have been ready for many years.'

I put the knife down.

'Immortal?' he murmured.

I nodded.

'And what have you -- done -- with this great gift?'

'Shared it.' I said.

'You poor, damned soul.'

I remained in that room for a very long time watching the old mans bones turn to dust. I think that my blood could have revived him even then, but I do not think they could have rebuilt his memory and I had no wish for a zombie as my companion.

I have learned much and forgotten much. It would not be wise for me to dream. All I can manage is half sleep, a meditation: thoughtless, dreamless, still. Like death. In this state I spent many years.

And finally, the one who I had come to earth to find, came to me. His words called me back to consciousness.

'It's been a long journey,'

Pale, like me; but so much more human. While I had wandered, he had lived among them.

'Not as long as it has been for me.'

'So. You kept your side of the bargain,' he said.

'I came home. But I couldn't find you.'

'I've slept, mostly, since the last civilisation fell. I thought that was the end of the story. I look out, every thousand years or so, in case a new one is starting.'

'I don't think these stories ever end,' I said. 'You took away the only ending there could ever be.'

'That sounded bitter.'

'It's not me who was the devil', I said, 'It was you..'

'Ah.' he said 'So I take it that you have answered the question.'

'No.' I said, 'I have no idea. But I have reached a decision. That may be the same thing.'

'I was surprised when it was a human that woke me.' he said. 'I expected it to be you.'

'A human?'

'A charming young man. He was on a sort of a quest. His people were ruled by eleven gods; who claimed to be ruling for a period of a thousand years, until their god returned to bring the story to an end. The eleven lived on a mountain. The chair left open by the one who had betrayed them and slain the god's messenger was still vacant and the eleven offered to share their immortality with anyone they thought good enough and holy enough. This young man had two elder brothers. Each had lived blameless, holy lives and each had, in turn, climbed the mountain of the gods, to try his luck in filling the empty chair. The first had been killed by the gods. The second returned from the mountain, blind and half mad. His young brother tended him for weeks and listened to him rave. And in his raving, he said something very interesting. That the gods had once been as mortal as you or I. Those were his words. And that they had borrowed their immortality from a wandering messenger of the gods. And that somewhere, there was a secret valley; and in that valley, an ancient shrine; and sleeping in that shrine, was the messenger of the gods. It was from him that the eleven borrowed their immortality. And he would give immortality away to anyone who asked. So the young man had set out to look for it.'

'Is that true?'

'True enough to give me a clue that you were back. And that you had broken our agreement.'

'Yes.' I said 'I wish that I hadn't, but when I did, I thought that it was the right thing to do.'

'Oh, it probably was. I broke my side, as well. The first couple of times they blew themselves back to the dark ages, I managed to watch dispassionately. There is an archive somewhere, with histories of a dozen different civilisations in it. The third time, they had come up with a really devastating new type of biological weapon. I think' he said, looking proud and wounded at the same time 'That their principles were based on some of my research. So I asked myself; do I really want to watch this happen again? I didn't take over, or anything. But you will spot my influence in the histories. If nothing else, a lot of them know that I am here and that makes a big difference.'

'I never managed to keep the questions hypothetical, either.' I said. 'Some of them offered me worlds in return for the secret. Others offered me fortunes to take it away. A tree whose roots covered three continents offered me an empire consisting of seven planets for a test tube of my blood. None of that ever tempted me. But faced with a good man who was going to die and knowing that I could save him, I could never resist that.'

'How many good men did you meet?'

'Thousands. Tens of thousands. If they passed their blood on to others, there could be billions by now.'

'So to the question, should we share the gift, is academic. You have already done so. And the question, are our own people worth preserving is also academic. How they would have prospered without the gift, we do not know. I tried to preserve them and failed. You have ensured that a few, at least, will survive. You said that you had reached a decision.'

'Before you gave me the injection, I asked you whether the process was irrevocable.'

'And I said probably not. Given time, I could probably come up with a means of reversing it.'

'And did you?'

He opened his backpack and took out a metal case. 'Yes. As a matter of fact I did.'

He argued with me, of course, but perhaps not very hard. We said our good-byes. He left me in the chamber in that ancient cathedral. I suppose he went back to the city of immortals, to tell them not to listen to me; that their way is best. He is wrong.

A week after he left, I received another visitor; a young man in search of a sleeping god who gave away life for asking. I told him that the story wasn't true; but I asked him to perform a task for me. He said that he would do so; that he would carry this message and the bottle containing the death-machines. I have told him to take it first to his eleven gods and then to the billions who I touched.

I thought I was freeing you from death; making you immune from time. But Nathaniel was right. I was trapping you.

I am sorry, Thaddeus, that I damned you so deeply for such a little thing, when I had done such a terrible thing to you, such a short time before.

I am sorry, to you, who worship me as life-giver and love me as saviour. I beg your forgiveness for what I did to you.

I choose to leave the universe, of my own free will. What I will see, ten seconds, a minute, from now, it is not possible to imagine.

I picture it as a park, with a metal gate, a quarter of a mile high. At its centre is the gigantic metal statue of a lion. Waiting for me is one who I picture as a very elderly human with hair that was once red.. He will look sad, because so few people have come to enjoy his garden. I think he will try to embrace me, but I will shy away.

'I spread a false gift.' I will say 'I trapped tens of millions. I ruined your universe.'

'Do you think I don't know that?' he will say 'We have a lot to talk about.'