Guys, follow the rules or get reported to Jammy, he's back and in needs to use his banhammer to get back into the gear of things.
As for killing the Greater Daemon:
Grey Knight Grandmaster with full anti-daemon gear.
Get into combat (full termy posse to deliver him), then get into CC. Incense and book, hitting the Greater daemon on 3's then wounding on 4's then, then you get inv, then when you fail it, instant gib, as DH Codex force weapons trump rulebook force weapons.