Ina, the cheating heroine.

almost a hundred level 1 units, upgrade them to level 2 on the second day – they’ll hold their ground. And you’ll have faster leveling than your opponent.

Hmm... It seems you're fighting against the AI as a Warrior... you probably won't outrun Orcs, Dark Elves (if you play with invisibility), or Machinists controlled by a human player, even with a hundred Warriors.