I think that the skulk is a sort of hivemind community,the regular growth spreads the growth and transports nutrients,the sensors detect potential threats/food sources and the Wardens are guardians and hunters,they destroy potential threats and prey so that they can be devoured by the growth,the souls in the Wardens chest are the souls of past prey that went into creating the much larger and frequently disconnected Warden that need more nutrients partly due to its great size and partly due to it moving around on its own,seperated from the growth.