labor of love
something done for personal pleasure and not for money
The man's painting is a labor of love and he does not expect to make any money from it.
Outrageous Werewolves Facts You Probably Never Knew
Outrageous Werewolves Facts 14
Similarly to the werewolf legends, in Viking Scandinavia, there were stories about the so called Ulfhednars, warriors dressed up in wolf skin, who were allegedly able to take over the spirit of the animals and use it in battles. They didnt feel any pain and killed their enemies in a frenzy like state.