Stream anime episodes online for free, Watch Slayers Next Episode 21 English version online and free episodes. Anime Episode guide, Chapter Slayers Next Episode 21 English dubbed The Thousand Year Old Truth! The Traitorous Demon Dragon King! Lina’s party gets away from the monsters and go into the cave where the Bible is supposed to be. Deep inside the cave, Lina enters the gate to the other side where the Bible is sealed. Martina rushes in to enter with her. Lina reaches the Bible to hear the truth about the Lord of Nightmare, which is the power source of Giga Slave and Ragna Blade. On the other hand, Gourry and others fight the monsters outside of the gate. Garv appears, injures Xellos, puts Lina in a pinch when she comes out of the gate.