as you level you get more chances for powers, from your zanpakuto, or if your a hollow, your body.
all powers must be approved, they cannot enhance your stats, unless they have a significant drawback, and you can't spam them forever in battle, so be responsible when using them.
a note on elemental powers, there will be no complete control of said element, you have separate attacks with it, like rukias three ice based attacks, there won't be any i can freely control all ice in the area.
like earned stats, you get extra powers at certain ranks, you must attain the rank or bonus, not just the level.
shinigami
unseated 0 powers
seated 0 powers
shikai +3 powers, total of up to 3 powers
lieutenant 3 powers
bankai +3 powers, usable only in bankai
a note for bankai forms, if your bankai is a huge weapon, like renji's fair enough, if it is a sentient creature with it's own stats, like mayuri's, then it will count as one of your bankai powers
hollows
hollow 1 power
gillian -+0 powers, 1 power
adjucha +1 power 2 powers
vasto lord +1 power 3 powers
whenever you choose to become arrancar, you get one extra power, which is useable only in pre release, and any other power must be used in release.
you can use all previous release stages powers in your final stage, so bankai has 3 bankai powers, and the shikai powers.
your level and rank will effect whether powers get approved, so no bankai level shikais, or arrancar level abilities used by hollows.