The Sleeper's actions throughout the series
The End of Time(beginning); Let us kill these two innocent children!!!
The End of Time(end); Hey Aru, one of the children I was trying to KILL earlier, why don't you join me!?
The Song of Death; I love and miss my child who is destined to KILL me.
The Tree of Wishes; Let us torture my child with loving memories to show that I really wanted to be a good father...
AND THEN KIDNAP HER MWAHAHAHAHA!!!
The City of Gold; Let us hold her hostage for 2 months in the middle of nowhere, brainwash her half-sister, and then ask if she wants to join us after crashing her birthday party, freezing everyone, INTERUPTTING AN ARUDEN MOMENT, becoming and overprotective dad, and turning her half-sister against her.
In conclusion, the Sleeper is a pyschopath.