Complex sentence: Eukanaria found the perfect body for Fulcanelli, which is the protagonist Haruhiko, and to Haruhiko's surprise, Eukanaria looks exactly like Yuka, and he himself looks exactly like Fulcanelli.
Split into simpler sentences: Eukanaria found the perfect body for Fulcanelli, which is the protagonist Haruhiko. To Haruhiko's surprise, Eukanaria looks exactly like Yuka, and he himself looks exactly like Fulcanelli.