Deckard Cain's Journal was a feature on the original Diablo III website. It narrated the events of Diablo, Diablo II, and Diablo II: Lord of Destruction from the point of view of Deckard Cain. The journal was taken down along with the original site.
The journal is partly out of date in that Aidan is referred to as a nameless warrior, rather than the prince of Khanduras he would become in later lore. Additionally, the years given by Cain do not match the current timeline (in which the events described go across years 1263-'65) nor the order of months (Kathon comes after Ratham in the same year). Regardless, the journal is recorded here for reference and posterity.
29th Day of Jeshasan, 1265 Anno KehjistaniEdit
The events of the past year are unbelievable and have driven me to again write my thoughts. No matter how hard I try, the facts are unavoidable: our King Leoric has gone mad, lashing out in crazed frenzy at the abduction of his son Albrecht, and our steady losses of the ill-advised war against Westmarch, leading to an open revolt among the guards. There is something almost palatable in the air. It feels like...terror.
1st Day of Dasnhar, 1265 Anno KehjistaniEdit
Can the old stories be true—can the tales of the brave Horadrim and the Lords of the Burning Hells be more than a legend, a fairytale told to me by my mother? I used to thrive on those tales of bravery and heroism. I'd imagine myself ; the mysterious Horadrim led by the inscrutable Tal Rasha! I was so proud to be the 'Last of the Horadrim', the one who would travel the world fighting evil wherever it dwelt. Ah, the boundless energy of youth.
Could there be some basis in truth to all these tales? The signs all point to this, but how is someone with my education, my knowledge, to take these tales seriously?
Is there really some dark entity buried beneath our town? If only my ageing mind could remember the tales as vividly as I did in my younger days.
12th Day of Dasnhar, 1265 Anno KehjistaniEdit
I am a fool. If I had acted sooner, if I had voiced my concerns, they would not be dead. Farnham would not be the drunken sot he now is. Lazarus, supposed Archbishop of Light, has led a group of villagers to their horrific end under the guise of searching for the king's missing son. Is he the architect of the evil that has befallen the town, or simply an unwitting pawn?
The nights are long and as I sit and listen to the hellish drones emanating from the cathedral, I begin to see my path clearly before me. I shall return to the texts. There must be an answer, a way to defeat this evil that torments us.
20th Day of Dasnhar, 1265 Anno KehjistaniEdit
Each new terror sends more townspeople fleeing. There are only a few of us left now. Griswold. Pepin. Ogden. Farnham, the unfortunate Wirt, and of course, the fair Gillian. There is someone else however, someone who has come while others flee. I am not sure what to make of this Adria, who openly calls herself witch. She has access to all manner of arcane knowledge that even I do not. Why has she come here now, at this heinous time? I feel there is something amiss about her.
27th Day of Dasnhar, 1265 Anno KehjistaniEdit
Every dawn seems to bring more adventurers into our midst. But none who can yet be called hero. I hide each time and continue scouring the old texts for answers. If only I had taken them more seriously, not dismissed them so lightly?
1st Day of Ratham, 1265 Anno KehjistaniEdit
Finally one of our adventurers seems to stand out from the rest. Though a man of few words he radiates a calm and focus that unnerve the others, who are only interested in pillaging and looting. I feel I have come to know this hero, this wanderer. I have revealed my history and shared my knowledge with him. I hope it is enough.
21st Day of Ratham, 1265 Anno KehjistaniEdit
I have suspected for a time now the true nature of the evil that is at the heart of our troubles, but it was too horrible to admit the truth of it. But the time for denial is past: it is the Dark Lord of Terror, Diablo himself, who plagues us.
The vile staff of Lazarus was brought to me today, further confirming my suspicions. There is no longer any doubt that he is the one who kidnapped Albrecht and perhaps even freed Diablo from his ancient prison. Who knows what further treachery he has planned? Luckily I suspect Lazarus has not long to live if our champion has anything to say on it.
6th Day of Esunar, 1265 Anno KehjistaniEdit
I dreamt of the death wail of a small child tonight. It tore up from the depths, shattering the windows of the decrepit cathedral. As I started awake, it became apparent that it was actually the shriek of Diablo's tortured end. Unable to return to my sleep after such an unsettling cry I ventured outdoors to await the warrior's return. He finally emerged, covered in blood - much his own, much his enemies'. I am greatly relieved he survived the ordeal and these horrible events are now in our past. But my mind is troubled, for could this not have been avoided if I had not dismissed my legacy so lightly?
18th Day of Esunar, 1265 Anno KehjistaniEdit
I have never seen Tristram bursting with so much joy in the weeks since Diablo's defeat. The town's quiet, brooding hero which I am proud to call friend, has humbly endured these celebrations. Yet it seems clear to me the scars he gained beneath the church run deeper than those upon his skin and may have changed him forever. I have offered counsel, but he remains distant. Time, perhaps, is the only thing that may heal him.
20th Day of Esunar, 1265 Anno KehjistaniEdit
How could I have been so blind? I believed my friend's melancholy to be a natural reaction of the horrors he lived. How could I not have seen that he carried within him the very being of Diablo? After brooding for weeks, he finally slipped away in the night. Perhaps he had gone to "the east" that he so often woke screaming about in the days following his victory over the Lord of Terror.
Shortly after he left us, legions of foul demons attacked and burned our town to its foundations. None of the townspeople were spared, and not even the women or children were allowed the peace of the grave. Instead, all were reanimated in grisly undeath. And Griswold, who had so faithfully armored the one I had called friend, suffered perhaps the worst fate of all, being corrupted into a slavering demonic beast thirsting after human flesh.
This is no simple madness. It can be nothing less than possession by the Lord of Terror himself. The fool, he thought he could contain Diablo's evil. His reckless overconfidence has proven costly to us all.
I sit now, caged, amongst the screams and the hellfire, as I await my own end.
2nd Day of Kathon, 1266 Anno KehjistaniEdit
Although I had long given up hope and surrendered to my inevitable fate, the impossible happened today. I was rescued. Heroes have come to Khanduras to combat the corruption of the man I've come to call the Dark Wanderer has brought upon these lands. He had long since departed on some unknown mission, but they could not follow until they defeated the vile demoness, Andariel, who barred the only passage east. I have decided to join them, in the hopes my knowledge of the ancient ways might be of some help.
28th Day of Kathon, 1266 Anno KehjistaniEdit
Our sense of relief is overwhelming now that our passage through the desert is finally over and we have arrived in Lut Gholein. Though I tell no one, Diablo's terror has left its mark upon me as well. I wake in the night, suffering unholy visions of the destruction visited upon my home, the slaughter of the helpless villagers, and the echoes of dark acts perpetrated beneath the earth. I hope that these will pass in time, but I fear I will never escape them.
I spoke with the people of the town for a clue to the whereabouts of my former friend, but information is scarce. We have learned that he does not travel alone: he has a companion named Marius. I can only wonder what part he plays in all of this.
11th Day of Solmaneth, 1266 Anno KehjistaniEdit
We are too late. My companions followed the trail of the Dark Wanderer to the tomb of Tal Rasha, only to be confronted by the demon Duriel. Baal's Soulstone was nowhere to be found. We can assume that Baal is free once again, and that he and the Wanderer have departed for Travincal to free their brother, Mephisto. This must not be allowed to happen.
1st Day of Montaht, 1266 Anno KehjistaniEdit
Today I have seen what has become of the man who once risked everything to save us from the Lord of Terror. It was here in the jungles outside Kurast that we caught our first fleeting glimpse of the Dark Wanderer. It saddens me to think that even as steadfast and noble a hero as he has proven insignificant beneath the corrupting influence of the Lord of Terror. I weep for what he once was, and yet I curse him for his arrogance that has led him to this path, sowing pain and death across the world.
Mephisto's resurrection in this world was brief; my companions have seen to that. They fought through horrors I can scarcely imagine to defeat him and reclaim his Soulstone. They also brought back the devastating news that the Wanderer was no more. All traces of humanity had been erradicated; he has completely been overtaken by Diablo in mind, body, and spirit. Fortunately they have succeeded in driving him back to his fiery home, and they tell me they mean to assault the Burning Hells in order to put an end to his existence once and for all. I can only wish them luck.
4th Day of Ostara, 1266 Anno KehjistaniEdit
Diablo is dead. I have long desired to hear those words, but now that they come, I feel little joy. News has reached us of a demonic army marching upon Arreat. This is Baal's doing, no doubt. We depart for the north with the tide.
Still, we must count our blessings: the Soulstones of Mephisto and Diablo have been destroyed in the Hellforge and they will trouble us no further. Only one remains.
The cold of the northern mountains chills me to my old and weary bones. Baal's army holds the mountain passes from our haven in Harrogath all the way to the summit. The honor, strength, and dedication of my companions never cease to amaze me. They are even now braving the demons and snow to reach Baal himself. Rumors of betrayal swirl through the town. This time, we must not be too late.
It seems we are cursed. Even in victory, we face defeat. Although the heroes defeated Baal, the angel Tyrael has delivered grave news. An object of great power he calls the Worldstone was held in secret at the mountain's summit, and it has been corrupted by Baal. He believes the only option open to him is to destroy it. I know too little of this Worldstone and what powers it may hold to guess what might come of this, but I fear our actions may scar the world in ways we cannot know. I pray Tyrael is making the right choice.