Jotunborn ancestry from Battlecry!

[Pagan priest]

Will the jotunborn ancestry need AcP to play, and if so, how many?

[Tomppa]

Highly likely that it will.
Generally speaking, uncommon ancestries require 80 acp, and rare ancestries require 160. There are a few exceptions though, but we'll see it when the book gets added to character options page.