mpo_release_herder_land_effect

mpo_release_herder_land_effect = {
	# Save scope of character triggering the effect
	save_scope_as = trigger_character
	every_top_realm_border_county = {
		limit = {
			title_province = {
				this != scope:trigger_character.capital_province
			}
		}
		add_to_list = target_titles
	}
	while = {
		limit = { # Loop over list of target titles until there are no more titles to grant
			list_size = {
				name = target_titles
				value >= 1
			}
		}
		random_in_list = {
			list = target_titles
			if = {
				limit = {
					title_province = { has_holding_type = nomad_holding }
				}
				title_province = { set_holding_type = herder_holding }
			}

			save_scope_as = county_of_origin

			create_character = {
				template = herder_character
				dynasty = none
				location = scope:county_of_origin.title_province
				culture = scope:county_of_origin.culture
				faith = scope:county_of_origin.faith
				rite = scope:county_of_origin.rite
				gender_female_chance = {
					if = {
						limit = { scope:county_of_origin.rite = { rite_has_doctrine = doctrine_gender_male_dominated } }
						add = 20
					}
					else_if = {
						limit = { scope:county_of_origin.rite = { rite_has_doctrine = doctrine_gender_female_dominated } }
						add = 80
					}
					else = {
						add = 50
					}
				}
				save_scope_as = new_herder
			}

			create_title_and_vassal_change = {
				type = granted
				save_scope_as = change
				add_claim_on_loss = no
			}
			change_title_holder_include_vassals = {
				holder = scope:new_herder
				change = scope:change
			}
			resolve_title_and_vassal_change = scope:change
			remove_from_list = target_titles
		}
		scope:new_herder = {
			change_government = herder_government
			if = {
				limit = { is_independent_ruler = no }
				#De-vassalise him.
				create_title_and_vassal_change = {
					type = independency
					save_scope_as = change
					add_claim_on_loss = no
				}
				becomes_independent = { change = scope:change }
				resolve_title_and_vassal_change = scope:change
			}
		}
	}
}

As written in game/common/scripted_effects/09_dlc_mpo_scripted_effects.txt.