Ritual is a breaker program which breaks 1 firewall for a cost of 1 PWR, but also triggers a random daemon when it is used. Ritual also has a passive effect which increases the probability of daemon reversal by 5%.
Ritual is a profoundly bad program, and you should not take it except as a challenge. If you do, you should install the Scrolling Daemons mod, because you will have so many daemons active, they won't all fit on the screen at once.
The problem with Ritual is that every time you use it, you risk a bad daemon like Validate, Paradox or Labyrinth, and even when you get weaker daemons, their effects stack because you will get so many of them. As compensation for all the daemons, Ritual costs 1 PWR less than Lockpick, which isn't much help when you also lose PWR to Siphon and Modulate, or you have use it more times because of Rubiks or Castle.
If you are intent on using Ritual, you probably want to have Central on your team to benefit from her Antiviral Proxy augment, and find Brimstone to reverse more daemons, Bless to reduce the duration of daemons, or both. Otherwise, you should acquire a different breaker program as soon as possible, and use that instead of Ritual; and before you do, you should seriously consider not hacking devices like Security Cameras or the Power Supply connected to a Beam Emitter or Infrared Emitter, because the penalty for just walking through is less than the daemon(s) you'd take from hacking them on average.