Unfortunately up until now Espada dont have a zanapakuto release. This topic was heavily debated by us in this forum. I was supporting the idea of them having a zanapkuto release + arrancar release, and it grew strong with Arro release . I felt that would be the differentiating factor between Espada and arrancar. But will this change with Vastolorde release I dont know .
You could always use a pre existing thread on Arrancars to discuss this topic .
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[MANGA] Becoming Arrancar