Hopefully someone better at analysis than myself can do something with this information. Here's my thoughts on things:
1) The skull said that the Peasant's death would spark in-fighting among the members of the group, resulting in two deadlocked sides; I believe this deadlock is the argument that's sparking in the most recent comic, setting up Roberts and Morgan as the two leaders. Which side will the others pick?
2) It may depend on their alignment: the skull took care to mention how much their law-chaos alignment would affect their actions in the debate to come, as well as how the least trustworthy were those not fully dedicated to either side.
3) The only clue we receive from the skull about any roles is that the Mystic is a deceiver who cuts all ties they've made. Given how Roberts is only acting against Morgan to help his family (and is only being asked to do so because of his status as an ex-soldier) it's a reasonable conclusion that he isn't actually the Mystic. Whether he's the obvious Soldier or if his role in the story is more complex and less obvious than that, I'm not sure.
Spoiler: Available Roles
Spoiler: Relevant Comics
"Blood of the Peasant,
whose role is to die.
Blood of the Philosopher,
who sees through the gods' eye.
Blood of the Soldier,
who does what they're told.
Blood of the Noble,
who funds the quest with gold.
Blood of the Vandal,
who leaves the path to burn.
Blood of the Mystic,
who makes the moral turn.
Blood of the Criminal,
who makes an example of things.
Blood of the Architect,
the one pulling the strings.
With these drops absorbed,
their story is set up.
Their sanctity entwined
within the Ronciever Cup."
"Those with lawful hearts
consistently side with what's true...
and the ones of chaotics souls,
will do nothing but lie to you.
But those are the constants,
the ones that never veer...
It's neutral pieces, Nicole,
who's wavering egos you should fear."
"Some within the group start to question or even fear what certain members might do with all the power an item might give. All the while, the challenges become greater, the tensions intensify, and the pain becomes overwhelming.Then, while they're at their weakest, the Peasant dies.
Though the Peasant's death does help complete the item, it also drives a wedge between the team. And as the two sides in a deadlock of morality, it is the Mystic who becomes the deceiver, breaking every bond they've made. The quest is over, the fellowship lays shattered, and the path of a new future is written."
Originally Posted by Read's Thoughts on the Roles