The entire narrative of "Berserk" (1997) is a grand flashback leading to one of the most horrific events in anime: The Eclipse. The series begins with Guts as the "Black Swordsman," a lone, vengeful warrior hunted by demons. The subsequent 23 episodes explain how he became this figure. Guts finds a home with the Band of the Hawk, and forges a deep, complex bond with its leader, Griffith, and its female commander, Casca. The core of the plot is the triangular relationship: Casca's devotion to Griffith, Griffith's possessive fascination with Guts, and the eventual love that blossoms between Guts and Casca.
The major turning point is Guts' decision to leave the Band of the Hawk to find his own dream, as he no longer wants to be merely a tool for Griffith's ambition. This act shatters Griffith's psyche. In a moment of despair, Griffith sleeps with Princess Charlotte, leading to his capture and year-long, horrific torture that leaves him crippled and mute. After Guts and the remaining Hawks rescue him, Griffith is a broken shell. Seeing Guts and Casca's love for each other, and realizing his dream is now impossible, his despair activates the Crimson Behelit.
This triggers the Eclipse, dragging the Band of the Hawk into a demonic dimension. They are told by the God Hand, a council of demon lords, that they are sacrificial offerings. To achieve his dream, Griffith must sacrifice them. He agrees. In a nightmarish sequence, the Apostles (demons) devour the Band of the Hawk. Griffith is reborn as Femto, the fifth God Hand. To cement his transformation and inflict maximum pain on Guts, Femto brutally rapes a horrified Casca. Guts is forced to watch, and in his enraged struggle, he loses his left forearm and right eye. The anime ends here, with a final shot of Guts, having somehow survived, now armed with a large sword and a prosthetic arm, beginning his quest for revenge. The lack of Skull Knight's appearance (who saves them in the manga) makes their survival in the anime an unexplained event, amplifying the shock and abruptness of the cliffhanger.