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Common sense wise and Sportsmanship wise, What do you think is the least amount of points you and your opponent each need if you wanted to field a heirophant?
Thinking of buying one but if I can't use it then why bother
You could play it in a 1500 point game. Though, it would be a bit crazy. Your opponant could take it down, but the rest of your force would be.... lacking. So, I'd say, wait until about 2500 points to start using it. That's high enough for you to get a decent army and for the titan to fill in the rest.
Well he cannot be more than 1/3 of the total cost set for the game, so 3000 should be in order.
Does it say that in his rules? And if you mean of the whole game 1500 points per side is 3000 points in the game.
You can't have it in any game smaller than 2000pts, the hierophant is classed as a warengines and you only get those detachments when you play at least 2000+ games, aminimum of 2500 is the absolute minimum I would advice at 3000 it gets a lot better an easier to field.
Abnd super heavy tanks cannot exceed 1/3 of the points either, but it might have changed