Friender is a robot dog who is an ally of Casshern.
Friender once belonged to a group of robots who had 'accepted the ruin' and calmly awaited it, but began to travel with Casshern when the latter accidentally killed them all.
Being a dog, Friender does not speak, but it is apparent that he is very loyal to his masters and his friends. When first traveling with him, he acts as something of an alarm for Casshern, warning or even attacking Casshern when the latter gets out of hand. He also cares for Ringo, and is seen playing with her. He becomes kinder towards Casshern later on, but continues his role as an alarm.