to complete hard you need to get 2 scrolls and use them on 40 and 50.
The key is getting passed 25 with no scrolls.
you need at least 8-12 swords 3-6 knights and 3 paladins,
but still it might throw too much at you, have to be a bit lucky.
then you have some time to get peasants to 40.
you should be aiming for 6+ pals, 20 sword 15+ knights.
i've only completed it with russians and celts.
got hydra rank.
just saw milsterV message. hes right got up to 1666%.
But i still think it should be 1550% for the badge
because thats the level of gold for 1 slice mode.
 "50 years (graphical)"){kind=icon}
 "3 Slices 2"){kind=icon}