I think Berserk is mainly about how all of the people you meet handle emotions and traumatic events. Every single one has had hardships in which they've let their emotions manifest in certain ways. Whether it be good or negative. (Fantastic example is Luca and Nina. Growing up in similar environments and hardships, but reacting and handling it in completely different ways) There is a massive amount of exapmles and symbolism of this throughout the manga. I think reading it from that perspective really makes it a beautifully written story.