Warhammer 40,000: Compilation (1991), p105 — Genestealer Cult Army List

1 Genestealer Patriarch as Oracle

Purestrain	M	WS	BS	S	T	W	I	A	Ld	Int	Cl	WP
	6	7	0	6	4	2	7	4	10	7	10	8

The Patriarch is the ancient Purestrain Genestealer who is the progenitor of the entire brood. He would be venerated as head, even if the brood had not become a Chaos cult. The fact that he is the head of a cult simply enhances his power as an Oracle - as it was he who made a pact with Chaos to gain power. He presides from a secluded shrine, directing the brood through the medium of the almost-Human Magus.

[...]

Daemonic Possession for Genestealer Patriarch

A Genestealer Patriarch may choose to be possessed by opening his soul and allowing a Daemon to enter. The points cost for possession is 500, regardless of the type of Daemon.

Possessed Patriarch's Profile

The profile of the possessed Patriarch is the average of the Daemon's profile and its own; the profiles of possessed Patriarchs of all possible Daemon types are listed below. The type of Daemon possessing the Patriarch depends on the Chaos power the cult has chosen to worship. Roll a D12 to discover the type of possessing Daemon of the appropriate Power.

[...]

Nurglesque Daemons

Daemon		M	WS	BS	S	T	W	I	A	Ld	Int	Cl	WP
1-4	Great Unclean One	6	8	5	6	5	6	8	7	10	8	10	9
5	Plaguebearer	5	6	2	5	3	1	6	3	10	8	10	9
6-10	Beast of Nurgle	4	5	0	4	3	2	5	D4+1	8	3	10	9
11	Nurgling*	5	4	1	3	2	2	5	3	7	6	8	7
12	Daemon Prince	Variable; see Possession in Realm of Chaos - Slaves to Darkness

* Note that a Nurgling base consists of more than one model (usually 7), but is treated as a single entity for possession. Possession by a Nurgling Base is an infestation by numerous Daemons, rather than by a single Nurgling.