Arrancar's won't be introduced yet, plus since you're new to the RP still, you'll need to stay in and be active for a certain amount of time before you'll be considered for owning an arrancar. The reason for this us so that we don't have people come in and let them have powerful characters since characters can still die in this RP. You can prepare a CS and show Kurisa but I highly doubt you'd be allowed to bring that character in any time soon.