
Quick answer — Hiroshi Ootake voices Boss in Mazinger Z, Zeno Zoldyck in Hunter x Hunter (2011), Nezu in Akira and 8 more characters.
Hiroshi Ootake voices Boss (Mazinger Z), Zeno Zoldyck (Hunter x Hunter (2011)), Nezu (Akira), Saotome (Maison Ikkoku), Pew (Treasure Island), Shichou (Little Witch Academia: The Enchanted Parade), Yattaran (Captain Harlock Space Pirate), Jijii (Pani Poni Dash!) and 3 more.
Boss is voiced in Japanese by Hiroshi Ootake.