Complex sentence: When he returned to Japan, there were several meet and greet events at Zepp Fukuoka and Zepp Osaka, where he sold special merchandise (including manga he illustrated and figurines, etc.).
Split into simpler sentences: When he returned to Japan, he organized several meet and greet events at Zepp Fukuoka and Zepp Osaka. He sold special merchandise (including manga he illustrated and figurines, etc.).