The “Maahir’s Gambit” scenario.

Simple and quick to play. On your starting tile, clear out enemies, build structures, but don't upgrade units; clear out the entire guild and immediately head towards Zoltan, leveling up only in the closest battles along the shortest route. Summon your upgraded army at the second magic fountain, and the rest is easy.
If I had known beforehand, I would have completed it much faster, instead of in 64 days.