Noriyuki Nakamura

A boy named Santa, born on Christmas Eve, meets Mai, a Santa Claus-in-training with an incredibly bizarre personality, on Christmas Eve. Romance blossoms.

Faaren is a peaceful and happy realm, ruled by a wise King... until the Demon Lord Ackdam overruns the kingdom with his black legions and terrifying dragon, killing the King and capturing the Queen. But the King's young son, Sirius, is swept away to safety and grows to be a powerful young warrior, tutored in the ways of swordsmanship and chivalry by his father's loyal minion, Rias. (myanimelist.net)

Nina, thinking it was a lolly, swallows an object called "Crystal Pearl". But the candy turns out to be a test for the magicians. To retrieve the crystal, a special medicine has to be made so now Zero and Ichii, the magicians, have to protect her from others while waiting for the medicine to be completed. (myanimelist.net)

Shiinya Kazuya died while saving young girls attacker, only to reincarnated into a world of swords and magic. It was a dream come true. He remembers his life and knowledge of Earth, now Cain von Silford, the third son of an aristocrats.