Aura of Slaanesh

In any hand-to-hand combat against the daemon enemies in base-to-base contact will become entranced by the Keeper of Secret's beauty and be unable to attack unless they take and pass a leadership test (2D6 against Ld in the same way as a psychology test). Test for each model fighting the daemon. This test must be taken at the start of each round of combat.

Greater Daemons

All the special rules for daemons apply as described in the Warhammer rulebook. In particular, note that the Keeper of Secrets has a saving throw of 4+ due to its daemonic intangibility or daemonic aura.

Terror!

The Keeper of Secrets is amongst the most terrifying of all monsters. The psychology rules for terror apply. Remember that monsters which cause terror automatically cause fear as well.