Dalek (The Waters of Mars)
This Dalek was one of the New Dalek Empire and created from Davros himself. (DW: The Stolen Earth) In the invasion of Earth, during the planet's forced relocation by the Daleks to the Medusa Cascade, this Dalek passed by Adelaide Brooke's house while her father was looking for her mother. Adelaide observed the Dalek, as it did her, and it spared her life, flying off. (DW: The Waters of Mars)
This Dalek presumably returned to the Dalek fleet in the Medusa Cascade and was destroyed when the Meta-Crisis Tenth Doctor committed genocide against the New Dalek Empire. (DW: Journey's End) The Tenth Doctor believed the Dalek recognised her as a fixed point in time. The event inspired Adelaide to go into space, to follow it, not for revenge, but to explore. (DW: The Waters of Mars)