First release of Zoroastrian Resurgence Karen Bloodline mod.
No DLC required nor recommended.
Requires The Old Gods DLC in order to play a Zoroastrian ruler, which you can obtain for free by subscribing to Crusader Kings newsletter by going to the official Crusader Kings website: Crusaderkings.com.
This mod replaces the original "persian.txt" (located in "Zoroastrian Resurgence") with a duplicate file that adds a few line to the first Karen character, that founded the Karen Dynasty, that adds the new bloodline added by this mod.