One of the things I like about Planescape is that with many of the fantasy character archetypes and philosophies, it's easy to twist them and turn them on their head yet have them still make sense. So one can make a real paradox of a character, yet have it make sense. For example,
1. The Altruistic Solipsist
This is a Signer, who naturally believes she imagines everything into existence, but also feels very responsible for the well being of others. Why should she if all the people she knows are fictional? Well, the fact that characters are fictional never stopped a lot of real people from identifying and/or caring for them. So logically, if a body imagines the multiverse into existence, she might also take responsibility for what happens to those in it. Empowered by making up for her harsh imagination, the Altruistic Solipsist takes to working to the someday when she'll be able to imagine a brighter world.
That might be one such an example of a paradoxically unlikely but logical character/belief twist, this one on the typically selfish Signer/”I believe the universe into existence” mentality. Let’s see how many more we can think of.
2. The Faithful Atheist(?)
A typical Athar factioneer who does not believe in the divinity of the powers.
What he DOES believe in though is the Great Uknown.
In fact he does not just believe in the Great Unknown like most Athar do.
He preaches about it to anyone who would hear.He builds shrines in it's name.His faith is so strong that he puts to shame even the archpriests of the so-called ''powers''.
In fact many Athar high-ups are starting to get peery about him and his strong faith and want to kick him out of the faction or worse...put him into the dead-book.