The lands of Barovia was always a place of darkness and supersition. It's people lived under the specter of death their entire lives; the things that went bump in the very real. As such their has always been a need for a knightly order to protect the helpless of the land. The Knights of the Raven was an order born to safeguard Barovia against any evil that might plague it and Siege Ravenloft was the order's home. The House that once proudly supported the order turned on the knighthod driving them from their ancestral Siege causing the order to all but vanish.
Your uncle, Konstantin Rallen, was the last of the Knights of the Raven and raised you from an early age when your parents were slain during the Summer of Sadness. The Siege had been left abandoned by the Zarovich line and your Uncle took you to the chapel in the castle to induct you formally into the order on your sixteenth birthday. You had barely been a knight for a year when the current Lord returned to the Siege to rule his lands after years of neglect. You and your Uncle fought bravely against the Lord's retainers but it was clear that you were no match for them. Your uncle ordered you to flee as he drew the lord and his retainers away. You made good your escape but in horror you watched him be slain on the battlements by a lieutenant of the Lord; Kavan the Grim. Kavan took your uncle's body and tossed it from the battlements in victory. The cruel warlord didn't even bother to take a trophy from your uncle, instead discarding his sword as if it meant nothing to him. You collected your uncle's remains later and laid him to rest in a secluded hollow in the Svalich Woods. You took up his arms and armor and vowed to stand vigil against the evil that once more crept into your lands.
You kept that vow as best you can, crossing swords with the retainers of the lord many times over the years. You have yet been able to best Kavan but each time you have been able to make good your escape to fight another day. You had begun to lose hope until a band of heroes arrived in Barovia to stand against the Lord and his darkness. You have joined their noble quest and look forward to the day when he is driven from your order's manse and you can begin the task of rebuilding your order.