Unsociable girl vs. shady boy + doppelganger-san! Yamamoto and Hattori. The two can't start a romantic comedy on their own, but... Hattori's doppelganger, "Doppel-san," will tell him what she's really thinking! Is Doppel-san the cupid of love? Or is she just a figment of his imagination?
Doppel-san is a completed manga by Oomi Tabi, first published in 2020. It blends romance, comedy and slice of life. You can read all 18 available chapters of Doppel-san online for free on MangaPulse; the newest is Chapter 31, added 2026-06-14. The series is finished, so you can read it from start to end in one go.