Glenn's Eberron Campaign
The Shadow Schism is the term used to encapsulate the formation of House Thuranni. Each Dragonmarked House contains many families. Baron Elar d’Thuranni (Elar Thuranni d’Phiarlan at the time) uncovered a secret plot of Tolar Paelion d’Phiarlan to assassinate the leaders of the Five Nations during The Last War, as well as all of the other families under House Phiarlan. After uncovering the plot, Elar rallied all of the Thuranni family and struck swiftly and mercilessly, killing every single member of the Paelion family. Elar himself struck down Tolar in the main House Phiarlan Enclave in Regalport (the capital of the Lhazaar Principalities). For their treachery, Baron Elvinor Elorrenthi d’Phiarlan Excoriated the entire Thuranni family.
Instead of sulking and accepting the punishment, Elar Thuranni formed a new Dragonmarked House, and styled himself Baron Elar Thuranni. Despite the vicious competition with House Phiarlan, Elar still maintains his household quite well.