Arjasp (ارجاسپ)

Turanian king and chief antagonist of the Keyanian era, Arjasp is what happens when someone hears “new religion” and decides the appropriate response is full-scale war. When Goshtasp converts to Zoroastrianism, Arjasp sticks with the old ways and immediately invades Iran, because ideological disagreement is apparently best expressed with fire and siege engines.

He turns the whole conflict into a religious showdown, less “let’s debate theology” and more “let’s burn cities and see who’s still standing.” In other words, your standard human reaction to belief differences, just with better armor and worse conflict resolution skills.