The event begins a seemingly random length of time after the following conditions have been met, and can only occur once per game:
- Kha'Zix has used all three evolution points (level 16 minimum)
- Bonetooth Necklace must be at 12 stacks.
- All members of both teams must be alive at the same time. 
Each champion is assigned to kill the other and the first to achieve this claims victory and is rewarded (assists count). The event can only occur once per game.
- The Hunt Is On!: Rengar must kill Kha'Zix first to become the ultimate hunter (assists count). Rengar stalks Kha'Zix, his greatest prize, and the one beast to have escaped him. If Rengar is victorious, his Bonetooth Necklace is replaced with an item called the Head of Kha'Zix, which provides the benefits of a fully stacked Bonetooth Necklace and grants Rengar increased vision range while in a brush. If Rengar is successful, he gains a buff with the title . If he fails, he gains a buff with the title .
"This twisted monster has evaded me for too long. I will have his head!"― Rengar
- The Hunt Is On!: Kha'zix must kill Rengar first in order to become the ultimate predator (assists count). Kha'Zix is ready to devour Rengar, his greatest prey. If Kha'Zix is victorious, he gains a fourth evolution point, which allows Kha'Zix to evolve all of his four abilities. If Kha'Zix is successful, he gains a buff with the title . If he fails, he gains a buff with the title .
"I have grown and adapted since I took his eye. I will feast on lion!"― Kha'Zix
- When the event begins, there is a chime and players receive a "Quest Received" notification similar to the Mark of the Conqueror quest.
- The event can only occur once per game. If both teams have a Rengar and Kha'Zix, the event will begin for the combination which meet the conditions first.
- The event will not begin until Kha'Zix has used all three evolution points. As these are attained by ranking his ultimate, Void Assault, level 16 is the minimum requirement.