Snipe them down

There was no need to make this harder than it needed, Ren focused his energy in his eyes and after activating his Human Eye he immediately drew his bow, sniping the Jakis one by one and killing them all of before they even noticed they were under attack.

It was a fast and clean way to kill them all off, and possibly even too mercyful for cruel vermins like them since they'd die too fast to even feel any pain.

The profits were only so-so though, as only 3 of them held demonic core worth any coin...