keyword_shortcode.php

<?php
function keyword_shortcode($atts, $content = null) {
  $custom_factions = array("Chapter", "Legion", "Regiment", "Craftworld", "Masque", "Clan", "Order", "Sept", "Hive Fleet", "Dynasty", "Kabal", "Haemonculus Coven", "Wych Cult", "Ordo");
  if (!empty($content)) {
    $titlecased_content = ucwords(strtolower($content));
		if (in_array($titlecased_content, $custom_factions)) {
			return '<span style="font-variant: small-caps; font-weight: bold;">&lt;' . $titlecased_content . '&gt;</span>';
		} else {
			return '<span style="font-variant: small-caps; font-weight: bold;">' . $titlecased_content . '</span>';
		}
  } else {
    return '';
  }
}
add_shortcode('kw', 'keyword_shortcode');
?>