They will find their power to love others, and to create and to enjoy beauty and goodness, is being drained from them. However, alignment will not be compromised. If you have not yet despaired, you will reach any destination in three times the normal time. Yet if you have given in, you probably no longer seek to travel. A referee might reasonably decide that no healing or restorative magic of any sort works here.
All creatures look more or less dead.
The locals seldom show feelings, and never show love. Faith communities exist and are dedicated to the pursuit members' self-interest. What is most likely to unite these communities is the attitude that kindness is weakness, and that goodness is an illusion or a sickness of the mind. These instead become ways in which a stronger being preys on a weaker being. The locals will know if the player-characters have ever harmed others simply for personal gain, regardless of professed alignment.