After the community indicated that Jayce's lore made Viktor seem "like a Saturday morning cartoon villain", his lore was rewritten to better reflect how Riot viewed their rivalry.
This makes Jayce the second champion, after Shyvana, to have their lore changed due to community feedback.
Jayce is the second champion to have his ultimate available at level 1,the first being Karma and the third being Elise; however, unlike Karma, Jayce and Elise can later level up thier ultimate similar to the majority of the champions in the game in order to increase its potency.
Jayce is the third champion to have access to all his abilities at level 1, the others being Udyr, Elise and Karma.
Jayce is also the first champion to have 8 abilities.
Jayce is one of the four champions who is labelled as both melee and ranged, the others being Kayle, Elise and Nidalee.
Jayce's dance is a reference to U Can't Touch This, which is a song by M.C. Hammer. A side-by-side comparison can be seen here.
Jayce's joke is possibly a reference to Gogeta's actions from Dragon Ball GT, where Gogeta tells Omega Shenron that he will, "Extinguish every single cell in his body," but instead fires confetti to him.
Jayce views Viktor, the machine-augmented scientist from Zaun, as a dangerous enemy to Piltover.
Viktor defeated Jayce and stole a powerful arcane crystal to power his creations. Jayce later created the Mercury Hammer and counter assaulted Viktor's laboratory, destroying Viktor's prototype weapons.