Before Lord Kieran's troop left Aisgarth, he went to the Tower of Doom, where he was keeping his prisoners. The tower had been built even before he was born and he wasn't sure how long it had been there. According to his mother, he was born during the time of war, when several demon lords were fighting against each other to rule the land of Asnar.
He was already used to witnessing blood and chaos since he was young, but the Tower of Doom reminded him so much of his unwanted memories of blood and torture. However, he would occasionally come here to release his pent up frustrations and annoyance. It was a perfect excuse for him torture his prisoners.
Over the centuries since he took over as the Lord of the Court of Nightfall, many changes were made to the Tower of Doom to satisfy his needs and to suit his preference when it comes to punishing and torturing his enemies.