Of the two "most powerful monitors", the mysterious Deathfin Du is the Deluvian one. Though he appears to have transcended monasteries, his initial training was as a Diamondfin.
A fictionalized representation of Du appeared in a final confrontation with Deathfin Unon at the end of the great work of Kua Toa literature, The Current of Teeth.
Du is fabled for having created a martial arts kick maneuver which he calls "Genocide Hurricane".
Side note: Genocide Hurricane may be the Blibaal-iest attack name ever devised.