House Cassalanter
"Public transport is not for the public"
A noble house of Waterdeep that rose to prominance seemingly overnight after a long string of misfortunes (suspicious much?). In reality, they made a deal with Azmodeus to gain obscene wealth in return for the life of their son Osvaldo and possibly also their other children if they could not pay him back in gold and souls.
In order to get out of their devil deal, they scheemed to gain the wealth of the Vault of Dragons and also murder 100 inhabitants of Waterdeep as a sacrifice for Azmodeus. Ultimately, they failed and their schemes were unraveled by Divine Shanks. Their whereabouts and current status is currently unknown, other than that they donated a significant amount of gold to Zardoz Zord (Jarlaxle) for some unknown reason.