Kronos

Kronos (alternate spellings Cronos, Chronus, or Kronus) was the Chronovore who destroyed Atlantis.

Biography
Kronos was the result of a forbidden union, made unlawful by the Ancient Covenant, of a Chronovore, Prometheus, and the Eternal known as Elektra. (PDA: The Quantum Archangel) He described himself as "beyond good and evil".

In the 1970s, the Master used a crystal named after Kronos to cause him to manifest so that (he thought) he might bind Kronos to his will. This failed and the Master went back in time to the last days of Atlantis. Kronos ruined the city. In the aftermath, he stopped both the Doctor's and the Master's TARDIS in the Time Vortex and, appearing as a huge, translucent female face, asked the Third Doctor whether he wanted Kronos to destroy the Master. The Doctor demurred, Kronos let him free, and the Master vanished into his TARDIS. (DW: The Time Monster)

During the Quantum Archangel crisis, Kronos created the persona of Paul Kairos, a student under Ruth Ingram and Stuart Hyde, to manifest upon Earth. Kairos, through miraculous talent, had reverse-engineered the Master's TOMTIT device, and created an enhanced version, the TITAN Array. He was stripped of the rights to his own invention, the quantum lattice, by Angeliqua Whitefriar, and was in a relationship with a fellow student, Arlene Cole.

As Kairos, he worked with the Sixth Doctor and helped end the crisis by shedding his human guise and attacking the Mad Mind of Bophemeral during a violent engagement between the Archangel and the Doctor. Following this, he allowed the Kairos persona to remain active as an independent being. (PDA: The Quantum Archangel)

Behind the scenes

 * The name Kronos refers back to Greek mythology; Kronos was the father of the Olympian Gods.
 * Kronos is similar to the word chronos meaning time.