Juno/Reverse Juno

Reverse Juno (レバース・ジューノー, Rebāsu Junō), also known as Helios (ヘリオス, Heriosu) is the Emperor of Tophet from the Reverse Timeline.

Unlike the original Juno, Reverse Juno actually carried out her plans of eradicating humanity before being sent back to the original Juno's timeline to repent for that sin.

Etymology
Juno is the name of the queen of gods from Roman mythology. It correlates with her position in the series as the textbook definition of a goddess compared to a CPU and her claims to being the strongest goddess.

Her preferred name of Helios comes from the deity personification of the Sun. It correlates with her position as the sun goddess.