PCs must be human, but otherwise any of the classes, descriptors and foci from the main rule book are allowed. There can be one, and only one Varjellen in the group (page 121 of the rule book) or one and only one mlox (page 42 of the character options book).
Most options from the Character Options book are allowed, with the exceptions of:
# Racial Options, except for the mlox
# Location based options
# Some Descriptors, such as Wealthy
Characters should not have any history before the wake up in the glass coffin. One of the main drivers should be finding out who they are, and how they arrived to the coffins. This does not mean that they cannot have memories, but it does mean that they will have no connections, real state or large posessions (a personal land vehicle at most), and no wealth.