Sasaki and Peeps

The cute little bird I bought at a pet store is a reincarnated sage from another world.

Given the opportunity to cross to another world with the power of magic, Sasaki brings modern goods to the other world and starts a business.

While traveling back and forth between worlds - earning money, training in magic, and eating delicious food - he aims to live a leisurely, slow life. But one day, on his way home from work, he encounters an alien being. He uses the magic of the Sage Seal to survive the battle, but his abilities are recognized and he is scouted by the Cabinet Office's Bureau of Countermeasures for Supernatural Phenomena.

Otherworldly fantasy x battle of super-power abilities x love comedy with an age gap (?).

There's also a magical girl, a neighbor JC, a coworker JK, a nobleman, a loli witch, a prince, etc…

It's a story that goes back and forth between the fantasy world and modern Japan, with all the tropes of the genre thrown in.

(Source: Bookwalker, translated)