Worlds and Monsters :
well, at first you have Monster types , from the nine alignments and with xp values of... a broad range
so, to build a character you choose one Monster type for each alignment, then you write down their Stats, Abilities ( with perhaps no stacking ) , or the like;
of course, to purchase a given Monster Type you will need money, or xp, or ap, or the like;
so, a low-level pc can purchase Monsters worth 15 xp, ( or so ) ,
while high level might buy Kirin, or Dragons etc
and your chr is the assemblage of the nine Monster Types.
things to clarify:
stack ?
how do pcs get ap/xp/gp to purchase Monster Types