Alternian history secret: Iron Infidel was the song that Signless worshippers (typically lowbloods) sang in his memory. However, the non-worshipping highbloods (who never caught on to this) remixed it into INFIDELS! and played and "sang along" to it to ridicule lowbloods.
“I’d rather laugh with the sinners than cry with the saints” — Troll Billy Idol