Ghost disciples are followers of Necrovarus. They worship Ectofuntus in Port Phasmatys. After worshiping the Ectofuntus you can talk to the disciples to receive Ectotokens. You may need a Ghostspeak amulet while talking to Ghost disciples, if you don't they say "wooo woooo wooooo woo". Note that Ghostspeak amulet is not required when collecting Ectotokens by right click them and select Collect. The ghost desciples, like most ghosts living in Port Phasmatys, have a green glow to them. The maximum tokens they can hold before forcing you to collect them is 65.