At least we don't see em get torn apart... oh wait...
He was a normal Japanese man who was also an explorer with his wife, Sumiko Fudo and their assistant, Dr Yamanobe. He's also the Father of Akira Fudo. Well... before Lan Asuka in Devil Lady.
Devilman manga
In here, Reijiro, Sumiko, and Yamanobe were exploring the Himalayas and find Demons frozen in ice. They burst out, killing them. Before they die, they witness the face of the the demon king, Zenon. frozen in ice! upside down! and with his many mouths open!! ahhhhhhhh!! (in Devilman:The Birth they see Jinmen.)
Devilman tv
Those eyebrows. Its like Kenshiro from Hokuto No Ken!
In here he, Akira and Miki Makimuras rents (Kozo Makimura and Akiko Makimura) were in the Himalayas and Akira falls into a ice place. He goes after him but they get slagged by Devilman/Rerasu/Daruni. And then... He died... AHHHHHHHHHHHHHHHH!!
Devilman Crybaby
In here he is a demon. In episode 4 he attacks Akira's mother while she was at the airport, killing her.
Later, Akira, in the Devilman form, kills him with a simple punch.