
Quick answer — Shouhei Kajikawa voices Dominic in SPY x FAMILY, Hien in Log Horizon, Satoshi Takahashi in Grandpa and Grandma Turn Young Again and 2 more characters.
Shouhei Kajikawa voices Dominic (SPY x FAMILY), Hien (Log Horizon), Satoshi Takahashi (Grandpa and Grandma Turn Young Again), Chan (Deadman Wonderland), Masaki Yamada (Re-Kan!).
Dominic is voiced in Japanese by Shouhei Kajikawa.