How does summoning work now?

[Zombs]

I can't find It anywhere. Can we still summon? And if so, does It break any of our special rules?

[Closet Skeleton]

There's no summoning in the DG codex. The Daemon Codex has summoning rules that can be used still but adding a non-death guard unit to the army probably disables the -1 Toughness contagion.

[Shandathe]

That having been said, organizing around the Nurgle faction keyword instead of Death Guard is perfectly valid and unlocks things like the Feculent Gnarlmaw, so there's synergies that may make sacrificing the Contagion worth it. Having The Plague Bells Chime ability applying to Mortarion is... unfriendly.

 

 

You can also go the other way and summon in some of the Death Guard's units (Possessed, daemon engines.... Mortarion's probably out of reach!) when you're running Chaos Daemons instead.