Campaign Mode strategy: At the end of the 9th Level on this world, we are to assume that you have garnered 27 stars for easily beating 3-stars on every level up to this point. If you could also see the previous levels, we basically made full use of two towers more often; the barracks and the cannon. With 27 stars, you can fully upgrade (passive upgrades with stars) the cannon, and at least get the 2nd upgrade of for your melee units (first is making them 3 units instead of 2, and the second makes them more durable). This is to prepare for the 10th level which has a mini boss like final wave.
The strategy for this level does not vary much from the earlier strategies. Basically, you are putting up melee unit on the road to serve as choke points for the enemy wave to build up clusters that the cannon would then obliterate. This is rather effective as fully upgraded cannons (with rockets) have the capacity to target the farthest enemies on the map – meaning it has great reach. The only downside is that cannons are rather expensive to upgrade. And without fully utilizing them and properly sequencing the upgrades, they can either make or break your play.
Make sure Fee is out of the road to avoid getting her killed. Put her on the site as seen on the image below as this is the best site she can effectively help control the crowd. During the 3rd wave, add the third cannon along with two archer towers near your base to help clean up whatever passes through your supposed choke points (which will bound to fail as they wouldn’t initially be able to cope up with the volume of enemies). Make full use of Fee’s wolf and Lancelot’s defense buff during the 2nd to 3rd wave to survive the holocaust. Avail of the increased range upgrade of the archer tower to increase the effective targeting range of one of your cannons. Build another last line of defense with a barracks to the site near your base.
During the 4th wave, you may add in more choke points to hold-in clusters of enemies on near the entry points. On our case, we’ve placed it near the right most entry point since we know that the mini boss will appear from this entry point. Additionally, add one more cannon and an archer tower on the fifth wave and make sure to fully upgrade them to prepare for the last wave. Any remaining gold at the end of the 5th wave can be spent on upgrading your barracks. Put up barracks on the remaining empty sites on the path of the mini boss, as they help greatly on slowing him down on his tracks. When he manages to get past the barracks, sell them and avail an additional cannon and fully upgrade it to speed up tearing down his HP.
Legendary strategy: This is rather hard to defeat especially with the limited resources you get to start with. Fee wouldn’t be of much help too with the sorcerer’s paralyze-like spell. Nonetheless, build cannon along its path with the rocket as this is the only effective tower to deal with it. Secure barracks near your base to keep those from the bottom entry point from breaching you. Have Lancelot and Bolton guard the base. Fee on the other hand should follow up on the boss whenever she can. Build at least two barracks, an archery tower near the base and upgrade your two cannons with rockets for maximum reach. Use your Heroes’ skills to deal additional damage to boss. Upgrade your barracks as soon as the soldiers die to have them respawn instantaneously.