Sol, the Angel of the Sun, is one of the four sisters who serve Binary.
She and her sisters work to keep the Celestial Powers at bay, and keep the universe in balance so that Cthulhu never awakes again. They have dealt with the Moon Lord, Cthulhu's brother, multiple times when he attempted to upset their hard won balance.
Sol is the least magical apt of the four, preferring her physical weapons over "Nasty, difficult to use gadgets and willpower." She is the most mundane of the four, but still immensley powerful.