Fractal is a daemon which, when triggered, installs daemons on 2 unhacked mainframe devices. The devices, and the daemons installed on them, are selected randomly. The locations of these devices are also revealed to the player, if they have not already been explored.
Fractal cannot install daemons on devices which are currently controlled by the agency, or devices which already have daemons installed. However, it can install daemons on devices which are rebooting, on inactive Security Cameras, and on Corporate Safes or other devices that have been looted without being hacked. If there are fewer than 2 eligible devices, then Fractal installs fewer than 2 daemons.
Fractal 2.0 is an archdaemon which can occur from mission difficulty 5 and onwards in Endless modes. It installs daemons on all mainframe devices at the start of the mission, including Security Cameras and other devices which normally would never have a daemon initially installed.
Fractal is a relatively weak daemon because it does no immediate harm, and sometimes does no harm at all. Most daemons it might install can be mitigated somehow; or it may install daemons on devices you don't need to hack anyway. Typically, you can mitigate against Fractal simply by hacking other devices first, so the daemons will be installed on devices you don't want to hack, if any. However, even if you trigger Fractal early, it may still be several turns before you have to deal with the extra daemons.
Fractal is riskier when you are using Parasite, as it may install daemons on devices you are already committed to hacking. If possible, avoid triggering Fractal while hacking other devices using Parasite, unless those other devices already have daemons. Fractal and Fractal 2.0 also make Oracle more dangerous, as they can install daemons on Security Cameras, which otherwise typically don't have daemons.
In a mission with Fractal 2.0, it is usually essential to find and hack the Daemon Database quickly. It will not be feasible to use Hunter or Taurus to avoid daemons entirely, so save these for the worst daemons. If possible, explore the whole facility to discover what daemons are installed on each device, perhaps using Cloaking Rigs to avoid hacking cameras, and use this information to plan which devices to hack in what order. Some daemons are best triggered together so their durations overlap; for example, Paradox, Modulate and Portcullis together are no worse than Paradox alone. You can also avoid daemons using EMP Packs or Dr. Xu's Subdermal Tools to disable certain devices without hacking them.
Fractal can occasionally be beneficial by revealing the locations of important devices; it may also reveal the location of an unexplored Security Camera, allowing you to hack it to gain vision on a new area. Both Fractal and Fractal 2.0 also give more opportunities to benefit from Central's Antiviral Proxy augment.