To get the Cyborg race in Blox Fruits, follow these steps closely. First, ensure you have 3500 fragments. You must also reach the second sea and be at least level 1250 to defeat the required bosses.
Next, you need to obtain the Fist of Darkness. This rare item can drop from a Sea Beast, though the chance is only 2.5%. Alternatively, you might find it in chests, but the odds are low.
After that, you need the Core Brain. Purchase a special microchip from the Arithmetic NPC on Half-Hot Half-Cold Island for 1000 fragments. Use this microchip to spawn and defeat the Law Raid boss, which has a 5% chance to drop the Core Brain.
Finally, go to the secret room on Half-Hot Half-Cold Island. Use the Fist of Darkness to unlock the Law Raid terminal. Enter the blue capsule, press the green button while holding the Core Brain. This opens a staircase leading to a capsule that sells the Cyborg race for 2500 fragments.
By following these steps, you can successfully get the Cyborg race in Blox Fruits.