Welcome to Japan, Ms. Elf! (MANGA) Vol 1 by Makishima Suzuki

Kazuhiro Kitase's main hobby is sleeping. Ever since he was young, he would enter a world within his dreams and go on exciting adventures. As he grew older, he became acquainted with a female Elf and the two have now been united through a Dragon's brand! As he wakes up one day, he notices a familiar figure sleeping next to him...the Elf girl from his dreams?! Join Kazuhiro on his new adventures through Japan with the lovely Ms. Elf!