"Are you ready to learn, lad?"
Spoilers from the books and/or film to follow!
Tilda is Tom and Alice's daughter who is introduced in 'Brother Wulf' where Circe wants to have Tilda for herself to drink Tilda's blood because of her lineage (The Fiend and Bony Lizzie from the mother's side and Zenobia and seventh son of a seventh son blood from her father's side).