From Beta Forum
4th difficulty
If you feel ambitious, we have a new, extremely difficult extension to the Guild Expedition for you...
Very hard, very demanding, very challenging and very rewarding... Please welcome the
4th difficulty!
4th difficulty is an optional add-on for the most determined, powerful (and resourceful) guilds that feel like they want do even more than just completing the usual 100% every week. As the new difficulty is meant to be a choice and not a necessity, completing difficulty 3 will still mean reaching 100% progress (although guilds and players that are powering through the 4th difficulty will be indicated on the list).
If you decide to give 4th difficulty a shot, prepare for defeating two waves of enemies with significant bonuses to their statistics in all encounters. Of course negotiation is also possible - it is costly and some encounters may require medals and promethium (depending on your age).
Rewards for solving encounters will be accordingly better. There will be no coins or supplies. Small encounters will give you Diamonds, goods, Expedition attempts and usable items. Large encounters will reward you mostly with buildings, Diamonds and usable items.
What's more, there will normally be only two possible rewards, so the chance is 50/50. Therefore the chance of getting a really good reward is much higher.
Please remember that the 4th difficulty is
meant to be extremely hard and demanding, so if you're more of a casual player, this feature might not be for you. We still encourage you to give it a try though!