Thomas Davenport (father; deceased)
Stephen Laurent (deceased)
Daniel was born sometime in the 1870's in London. When he became old enough, he was inducted into the Order, and later he became the lover of Stephen Laurent.
In "A Whiff of Sulfur", When seeking to secure his position in England, "Alexander Grayson" made contact with Daniel and Laurent while they were out at a club, subtly blackmailing Laurent into selling his shares in various oil companies to Grayson or he would go public about their relationship. In "Goblin Merchant Men", Attempting to secure his position from future attempts, Laurent ended their relationship, prompting Daniel to commit suicide as he couldn't live without him. Daniel's death has left his father with a particular vendetta against Grayson.