Tomas Tod is Vladimir Tod's father and Otis Otis's brother. He is old friends with Vikas and many of the Russian vampires. He is a very old and powerful vampire who was around during the middle ages. According to Vikas, Tomas came up with a way to find humans who were not affected by the Black Plague, also known as The Black Death. He and his wife, Mellina were assumed dead when his bedroom burned in a fire, but later appeared in Twelth Grade Kills. In Twelth Grade Kills, Tomas Tod appears to Vlad in Nelly's home suprisingly. At first, Otis and Nelly are mad at him for all the things he did to Vlad, for causing him so much pain for years.
Tomas, after the battle between the Slayers and vampires, then tells Vlad the truth. What he was really after. He was the one who caused Mellina Tod's death, along with Vikas, the one who killed D'Ablo and Enrico, the founder of the group that supported the coming of the Pravus. Tomas wanted the Pravus' power for himself. He lead Vlad, Henry, Joss and Otis to the place where D'Ablo once tried to gain Vlad's invincibility. He threatened to kill Nelly if Vlad didn't kill Otis, and continue what D'Ablo started. Otis offered to give up his life, but when Nelly tried to reach out to Vlad, Tomas sucked her blood and killed her. While Joss and Henry took care of Vikas, Vlad followed Tomas. He tried to kill Otis, but by using the stake Joss had given him, Vlad killed Tomas.
Through out the entire series Vladimir has a black cat named Amenti. She had a chair she would sleep on all day and such. When Thomas Tod had returned Amenti would come and go. The day after the night that Thomas stopped Vlad from almost killing Joss, Amenti had disappeared. (This is total speculation) During the earlier books Otis had said that Vampires can turn into animals. I believe that Thomas Tod was Amenti. That is one piece of evidence, another is she disappeared after Thomas Tod’s death, and third Thomas had stated he watched Vlad growing up even if he hadn’t noticed.