Parasite

"Are you saying he can't be saved…?" the Hunting Guild members questioned in worry. "It doesn't seem like we have the time to gather new Soul Herbs for a different pill." 

"You would have more time if you didn't try to kill him early," Number One commented with an eye roll and began roasting the Inner World experts with no mercy. "Tell me, who was this smart to feed your brother with so many garbage pills? Do you realize how much impurities he consumed? It's not even the poison that was killing him but it's all the pills you gave him." 

"What do you mean…?" The Hunting Guild members got taken aback and displayed a few pills from his Storage Ring. "We had to feed him something or else he would die of starvation. He couldn't just survive on water alone."