[HMM I OFF TOURNAMENT] "Company"

you need a large population, either from many castles or from one castle with +5 dragons. But anything is possible.

If you attack with a red rush on day 10, you need enough troops from two castles built for cavalry (the third castle is only building the guild for the Portal), although it might even be easier with dragons, as +5 are generated easily. I managed to complete it in 7 days, i.e., on 3-1-5 (I didn't optimize the rest at all), but I didn't have time to check if it's possible in 6 days (the temptations are great). Also, the guild was built only on day 6, not day 5.