Earlier this year, before Sett’s release, Riot Games introduced an item called “The Call of the Boss” in League of Legends. By obtaining this item, you would unlock the new champion Sett at the time this “high-end brawler” officially debuted.
It seems that Riot Games will apply a similar approach for Lillia as players on international League of Legends forums have started receiving the item Lillia’s Haiku, similar to the previous case with Sett. Many theories were proposed earlier, such as relating to Thresh or the Water Dragon map, but the truth is much simpler; you just need to jungle and achieve enough kills to receive this item.
Specifically, a North American player with the Reddit username “dampmemelord” conducted an experiment and concluded that the requirement to obtain Lillia’s Haiku is to play in the jungle position and achieve 350 kills. Note that this number of 350 kills counts in normal matches, ranked games, and even against AI. If you play on the ARAM map or take Smite but do not jungle, it will not count; this makes sense since Lillia is introduced as a jungler.
The simplest way to complete this challenge is to play against AI and choose champions with good kill potential like Master Yi, Jax, Rengar, or Kha’Zix to maximize your kill count. Remember, you need to ensure that the number of monsters you farm from the jungle is sufficient for the game to recognize you as a jungler; if you farm too many minions in lanes, that game will not count (it is predicted that jungle monsters must account for at least 1/3 of your total minion score).
If you find another way to obtain the item Lillia’s Haiku, feel free to share it in the comments!