How to block/disable WiFiKill effectiveness on WiFi network?
Pretty much.. no. WiFiKill uses ARP poisoning to cause computers on the local network segment to use the wrong MAC address for the router, resulting in all packets being dropped. A second device running WiFiKill would have no visible effect; however, if you could spoof ARP reply packets which have the correct MAC address in them it could be used to mitigate the effects -- maybe. The two devices would be in a race at that point.