Sou joined UntroD Capital Japan, which operates Real Tech Fund, in 2015 as one of the earliest members. His major portfolio companies include QD LASER (listed on Tokyo Stock Exchange Mothers), which develops retina scanning-type eyewear, Kyulux (Kyushu University-based startup), which develops next-generation organic EL materials, and Ball Wave Inc. (Tohoku University-based startup), which develops innovative chemical sensing technologies. In 2020, he led the creation of the Glocal Deeptech Fund (Real Tech Fund No. 3), which invests proactively in local Real Tech startups. He aims to resolve global issues whilst energizing local economies by supporting startups with participating companies of the fund, such as local financial institutions and operating companies. He was appointed as Executive Director of UntroD Capital Japan in 2022. Since October 2026, he has served as Partner, leading the Real Tech Fund.

Before joining the company, he was in charge of corporate planning at a R&D-type semiconductor startup.

He has a Bachelors in Economics from Tohoku University.