I can understand that many fans of Demon Slayer might have been emotionally impacted by the deaths of various Hashira (Pillars) in the manga.
there were several emotional deaths of Hashira in the manga. For instance, the death of Shinobu Kocho, the Insect Hashira, was particularly impactful for some readers due to her compassionate and gentle nature. Similarly, the death of Kyojuro Rengoku, the Flame Hashira, was also highly emotional, as he played a significant role in the story and displayed great bravery during his final moments.
Keep in mind that there might have been more developments in the manga after i lost interest in that topic, so there could be additional emotional moments that I'm unaware of.