Shin Honkaku Mahou Shoujo Risuka

The elementary schooler unlike any other, Kugi Kizutaka, is searching for "useful pawns" in order to achieve his own ambitions, comes to learn of Mizukura Risuka, a magician with the title "The Red Witch of Time." Risuka had left the Kingdom of Magic through the Gate, chasing after her father, a great mage called both "a God" and "a Demon." An unpredictable and unchained magical tale!

(Source: Kodansha, translated)

Note: The serialized chapters 16 and 17 were merged into one chapter in volume 5.