Truth

Then, not long ago, after Thomas' parents died, Jacqueline knew Thomas will annul her so she confronted him by inviting him to the cruise ship. How can he not sense her killing intent? Thus, that night when they were talking at the deck of the ship, she finally made her move. She tried to push him, but unexpectedly the ship rocked and she fell to the water – to her death.

When he woke up, he became a ghost. Fortunately, his soul was attached to his corpse thus he later was reunited with Thomas. But, he can't talk to him, and he can't see him. However, once when Thomas left, he tried to follow him, he was surprised to find he can finally detach his soul to his corpse. Thus, he became Thomas' little tail.