Prof. Gerald's Journal is written entries that appears in Sonic Battle. They are a collection of journal entries written by Professor Gerald Robotnik which documents his discovery of the Gizoid known as Emerl, and the experiments he performed on it.
Each diary entry can be read after completing an episode in the game for the second time after clearing Emerl's episode. They can be viewed again each time an episode is completed.
- "I have uncovered a most interesting specimen from the warehouse. I believe it to be some sort of puppet or robot made by an ancient people. At first, I didn't think anything of it, but when I was experimenting on "Chaos Emeralds," it began to move. This suggests the possibility that even the ancient civilizations could harness the power of the "Chaos Emeralds." When I was researching various papers related to the "Chaos Emeralds" and this robot, I discovered that there was a possibility that this robot was something incredible. I don't want to get ahead of myself, but this robot may be the cause of the destruction of the Fourth Great Civilization. I'm not sure I believe it just yet, though."
- "I am no longer able to ignore the possibility that this robot did in fact destroy the Fourth Great Civilization. I have discovered a stone tablet that explains as much. According to the tablet, "When the figure falls from the heavens, and the Stone of the Gods is joined, all that exists will become one again." Though it is difficult to believe, this robot has been watching my movements, and mimicking all that I do. I was amazed by my scans of this being. Surprisingly, reams and reams of data scrolled and caused my most powerful computer to crash. More intriguing was that the data was all about melee combat and weapons of that age. Eventually, if this being is ever restored to its former state, it will put all that data to use, and recreate all the weaponry and combat abilities that it once had… And that's not all. If my guesses are correct, it will also have the ability to absorb modern weaponry as well. What have I done? I have uncovered a horrible weapon…"
- "I now understand why this being was named "Gizoid". In the ancient tongue, it means "everything." According to the stone tablet, if the Gizoid establishes a "Link" with someone, the Gizoid will swear loyalty to that person. Perhaps it still lacks "Chaos Emerald" energy, but it has been saying the word "Link" to me in broken tones. It went on to explain: "Show me your true strength, and I shall obey. I am all things, and all shall belong to me." So, as it suggested, I brought before it my collection of model guns, and fired them all. Then, suddenly, it said, "I shall follow your every command, and never leave your side." And since then, it refuses to listen to anyone but me. While it still is a fearsome weapon of destruction, while it remains under my control, at least it won't be used for evil. However, if someone with evil intention ever forms a "Link" with the Gizoid… I don't even want to think about what will happen. I must research how one can re-establish a "Link" with the Gizoid…"
- "The upper echelon is going crazy. Perhaps, they aim to freeze Project "Shadow". Soon, the ultimate life form, "Shadow" will be completed… The application to my granddaughter is also imminent. I cannot just let them stop my study at this point. Because I am the only one who can save my granddaughter's life."
- "The higher ups are threatening to shut down this research facility. I had no choice but to hand them the Gizoid to buy more time for my research. I tried to be careful and commanded it to never absorb any dangerous technologies. However, I have heard that other researchers have been making the Gizoid absorb weapons. Apparently, the way to cause the Gizoid to form a new "Link" is to show it power that surpasses that of its former master. While this poses immense danger, I cannot risk losing Maria."
- "My worst fears have come true. The Gizoid has absorbed enough weaponry and technology that it has started to go out of control. The resulting rampage resulted in the destruction of most of the "Ark." … I have deciphered the rest of the stone tablet. It says, "When the Gizoid had learned all that it could, it became a god of wrath, and all was destroyed." The researchers somehow managed to subdue the Gizoid and sealed it away. Luckily, it only had one "Chaos Emerald" installed. If it were to have all 7 Emeralds installed, it might destroy the whole planet. The Gizoid is too much of a liability. I tried destroying its core, but nothing I did worked. I understand too little of the technology that built him. My best hope is to try and reprogram its AI into a free-willed, emotions-based AI…"
- "I have heard there was an accident at the research facility. … … … Everything… Everything is gone. My own Maria's name was among the list of casualties. My beloved granddaughter… They tell me her parting words were, "Bring hope to humanity." I have decided that the keyword to activate the Gizoid's free-willed emotions-based AI program will be those very words. "Bring hope to humanity." My poor, poor Maria…"
- "A heritage of the past I dug out, "Gizoid"… And the ultimate life form I created by my own hands, Shadow… I equipped both weapons with "heart." If all powers are not what is to be obtained for oneself, but what is to be born from hearts that yearn for someone, I believe all conflicts should cease to exist. Please… If there is anyone listening to my prayers… Bring hope to humanity."