Complex sentence: Realizing and accepting this, both Nyssa and Talia became and are now the heads of the League of Assassins with Talia disavowing all her love for Bruce Wayne and both sisters declaring Batman to be their enemy.
Split into simpler sentences: Realizing and accepting this, both Nyssa and Talia became the heads of the League of Assassins. Talia disavowed her love for Bruce Wayne, and both sisters declared Batman to be their enemy.