Before we delve into Arcane's new idea of wild runes, let's start with the basics for context. The arcane is the powerful magic that is derived from the realms in League of Legends.In Arcane, the ...

In Act 1, Jayce talks of 'wild runes' to Ekko, describing them as the Arcane's fingerprints; more raw and natural than the ones he uses in Hextech.

I suspect we'll learn more about wild runes as season 2 progresses. For now, this is as good an explanation as we'll get. Arcane season 2 act ending explained: what is Viktor's new mission?

When Jayce is trapped in the pulsating wild rune in Arcane season 2's third episode, he sees a quick flash of the person who saved him when he was a child.