This is just stupid as a plot point. So only THEY can seal curses and save people, but they DON'T for the stupid reason they want the Kamite clan to get destroyed. They knew the Kamite clan's power is to just take out curses and seal it in their bodies so they used that to have the Kamite clan self-destruct and then come swooping in like heroes to seal the Kamite clan's family members once they are full of curses. It's even worse that it looks like they planned to actually increase the curse around that MC had to deal with just so his hand gets over its capacity. What horrible people.