I found the definition online and it has three parts to it, maybe the event has three parts?
So is this the rules
Wish Granting
After a person fulfills three of Alluka’s requests, Nanika will assume control over Alluka’s body and grant one wish. The wish doesn’t have to come from the one who fulfilled Alluka’s requests, as even an extra party can have their wish granted as long as it was declared during Nanika’s appearance. According to Killua, the degree of wish that Nanika can grant is probably infinite, going from briefly levitating a person into the air to altering probability and reality to make any effect occur.[2] Nanika is capable of effortlessly teleporting someone to another continent[1] and is also able to lift Gon’s vow and heal his mangled body.[9]
However, the greater the wish made to Nanika is, the harder to fulfill the next three requests will become. The one that must bear the burden of the next three requests is not the one that Nanika granted the wish to; it is the next person that Alluka makes requests to. If that person declines or fails to fulfill Alluka’s requests four times, at least two people will die with an increasing amount of casualties correlated to the scale of the previous wish. All deaths occur instantly and simultaneously.[2] Firstly, the request recipient and their most loved one will die from being crushed by an invisible force, and any additional deaths are chosen based on persons who spent the most time with the request recipient, regardless of their relationship to them. Unlike the recipient, they are wrung to death instead of crushed.[3] One example is when Kasuga, a servant of the Zoldyck family, failed to fulfill Alluka’s requests four times, the cost of the billion Jenny wish made previously by another servant, Yasuha, was transferred to her, and thus she, her lover, and 65 people that had spent the most time with her throughout her life were killed.[2]
Originally, there are five rules about Nanika’s power known by the Zoldyck family as a whole from their trial and error experiments as the expense of their butlers:
If someone fails to fulfill Alluka’s requests and gets killed, the difficulty level of Alluka’s requests returns to level 1. That is the best time to make a wish.
If Alluka is making requests from a particular person, they cannot be moved over to another person mid-way. Therefore if that particular person disappears such as concealing themselves, Alluka is unable to make requests to anybody else.
If the person fulfilling requests dies mid-way, it will count as a failure and at least one more person will die.
Alluka cannot make requests of someone without knowing their name.
The same person cannot ask Alluka for consecutive wishes.[5]
There are also rules initially known only by Killua, before he was forced to disclose them or they were puzzled out by Illumi:
While Nanika can grant only one wish at a time, Nanika can be given several conditions to a single wish, therefore greatly expanding the capacities of what one can ask of Nanika before granting another 3 requests.
If a wish is made for healing, Nanika must make physical contact with the target.[5] Furthermore, there isn’t any sort of cruel backlash, although this may be a rule Killua made up to hide his special privileges. It is also shown that healing is very taxing to Nanika, causing Alluka to fall asleep from exhaustion.[6]
Killua, due to his relationship with Alluka and Nanika, is the special privilege of issuing a “command”. When he does, his request will bypass any existing backlash and will be granted without any repercussions. If somebody else wishes other than Killua, they will suffer the same repercussions of the previous wish that was supposed to be given, with the command itself not affecting the requests.[1]
Issuing a “command” allows Killua to have his wish granted even if Nanika is in the middle of making requests of someone else,[5] as well as if it is his second consecutive wish.[1]