Time Magic
The true nature of Time magic is unknown and unknowable. The Time Core, the Core of Chronos, does not exist in any timeline. At the moment of creation, the Time Goddess put Chronos inside her own soul. The Time Goddess is known by a myriad names in the myriad timelines. She is not present in the Pentagonal Dominion, as it is but one grain among infinite on the beach of time.
It is assumed by mortal philosophers that the Time Goddess has eight powers and a specific Spirit-only power, just like the other cores. However, it is up to speculation what these powers are. Best guesses include Merging (possibly how she travels through time), Time Speed Manipulation, Time Stopping. Timeline Creation, and Fate Command.