Devilian: How do I block friend invitations?

Players can turn off or block friend invitations from within the 'Options' menu by using hotkey 'O' and navigating to the 'Player' tab in the 'Game Settings' section.

Once there players can choose to decline friend invitations by checking the box next to the option. Players can begin to accept friend invitations be unchecking the box, or using the 'Reset Tab' option.