Casca

For the first few dozen chapters, which make up the legendary Golden Age arc, Berserk actually reads like a gritty but grounded historical war story about found family.

Guts, Griffith, and the brilliant unit commander Casca form this incredibly tight, complex, deeply emotional bond.

Guts finally finds a place where his violence serves a purpose other than just his own survival.

But then an event called the Eclipse happens, and suddenly the grounded war story is violently ripped away, revealed to be merely the prologue of a cosmic tragedy that was already written by fate in a place Guts couldn't even see.

Within the rules Miura established, it is horribly, terrifyingly coherent.

Griffith's ascension is paid for with the specific blood of the people who trusted him.

Casca's trauma during this event is the most argued and analyzed scene in the series, but she is the character who understood the band's structure and Griffith's dream most clearly, making the violence against her a catastrophic, symbolic breaking of that entire structure of trust.

Guts survives, barely, but he is branded.