In the time I've been playing here, I've also met paladins of most different types. Some of them were straight and shiny good. Some were even considered as evil for their acts and earlier decisions.
That made me reflect also my own RP with one of my toons. Also I'm in this way looking for tips and advice how to do it right...or wrong. I read most of all, you loose your paladinhood, if:
a) You perform acts of evil.
b) You stop beeing lawful.
c) You do both.
The consequence is normally that you fall from grace as a paladin, but you're not necessarily abandoned by your deity.
Which means, you have to pick a different class or be an oath breaker. In both cases you loose all your spells and paladin abilities. But you still can worship the same deity if you want.
So my question is. How did you play your paladins, no matter if fallen or not?
