Don't mind me with a drive-by question but, hypothetically, if I wanted to start an army, Tomb Kings, and I bought the starter box but wanted to round it out, how should I do it?
I literally do not know the rules but a coworker plays 40k so we talk about Warhammer.
All I know is that there's some sort of thing where you can do Mortuary Cult or Royal Host and then saw a post mentioning "Grand Army". I'm guessing that means you just bring whatever unit you want but you don't get the bonuses of the other army rules.

Anyway, what I'm aiming for is hordes of skeletons so I don't know if Mortuary Cult for the ARISE! is better or if Royal Host gives bonuses to regular skeleton warriors and archers.
I wanna bog down the enemy in Skeleton Spearmen and shoot them to death and run them over. 2 screaming skull catapults.