With the spoilers for Black Clover chapter 347 out, it seems like Mangaka Yuki Tabata finally wants to end the speculations surrounding the Yami clan massacre. As the manga itself is on a break this week, the spoilers shouldn't have been leaked this early, however, with them out, fans were delighted with the revelations made through them.
The previous chapter saw the Ryuzen fighting the five-headed Sacred Dragon after they were warned about the Paladins' attack a day prior by the Shogun Ryudo Ryuya. He even had the Ryuzen Seven evacuate the citizens, avoiding any casualties. As for the Dragon, the five Ryuzen Seven members were together able to defeat it.
Disclaimer: This article contains spoilers for the Black Clover manga.
Black Clover chapter 347 reveals Ichika to be the one responsible for the Yami clan massacre
The spoilers for Black Clover chapter 347 revealed the Paladin Yrul launching an illusion spell at the Ryuzen Seven, which caused them to face their fears. This spell caused Ichika's father, the head of the Yami clan, to appear before her. While Ichika admitted that she did fear her father due to his abuse in the past, she was adamant that the spell wouldn't work on her as she knew it was just a deception.
However, the spell triggered Ichika's memories from her childhood. She could see how her father would get angry over the absence of war. As a solution to this, her father thought of having one of his children go berserk in the country.
Thus, he brought out a secret medicine passed down from generations in the Yami clan. The medicine was supposed to draw out the demonic potential of the clan members to help them go berserk with strength.
Initially, Ichika's father tried to give the medicine to her brother Sukehiro, however, he refused to consume it, soon after which she saw her father forcibly feeding her the medicine. Her next memory was of people running away from her during the Yami clan massacre. The last of Ichika's memories were of her father complementing her, "as expected of my child, Ichika."
Considering how these were Ichika's memories, it seems like Ichika was the one responsible for the Yami clan massacre under the influence of the secret clan medicine her father forcibly fed her.
Given how Ichika was still a child at the time, it seems like her brother Sukehiro took the blame for the massacre so that his sister would not be exiled from the country. Moreover, it would have been traumatic for Ichika to learn that she was the one who massacred her clan members at that age.
Thus, Yami Sukehiro, believing that Ryudo Ryuya could protect his sister, may have been in cahoots with his friend. While he may have requested Ryuya to take care of his sister, he would take the blame for the Yami clan massacre and leave the Land of the Sun.
Since then, Ichika and the Land of the Sun have been under the notion that the runaway clan member Yami Sukehiro was the one responsible for the Yami clan massacre, but in acuality, the one responsible for the same was the head of the clan, Ichika and Sukehiro's father, who force-fed her daughter a medicine, causing her to go berserk and massacre the entire clan.