Hidden Cities - 1
This is one of the simpler stages to clear. However, be advised that there is a Chaos Gate on the western island, so don't be too hasty.
Send a unit down each of the branches of road leading from your base and send a third unit south all the way into the mountains, as there is a hidden Temple in between the mountains and the fork in the river. In that Temple, you will meet Yushis, an imprisoned Cherubim. If your reputation is high, she will join you.
Among the enemies should be Werewolves, Evil Ones and Undead, but you should have no problem decimating them, especially if you have a lot of Sunshine items. It would be a good idea to revisit the City of Malano stage, take the Book of the Dead from Malano, and trade it in the Borders of Sharom stage for an Undead Ring. The Ring will turn one Sorcerer into a Lich, and Liches, boys and girls, are Super Happy Big Turbo 100% Powerful.
Anyways, with those three guard units in place, use your scout to liberate everything else, as it will be out of the enemy path (although Shad Dob, southeast of the Temple, may very well be attacked). Between enemy waves, send your strongest unit down to the enemy base in the southwest. I said it wasn't hard, didn't I?
Omicron will get to hit your party with two area-attack spells, but he's not exceptionally hard to kill. He's weak to White Magic so Yushis is the perfect choice for a supporting character. If you don't have her, use the unit with your own Sorcerers. Acid (Physical attack) will do around 50 damage per cast, and thus you should be able to kill him before he gets to his second spell. As you can see from the screenshot, I have one Lich at this point, making the battle even easier.
The Evil Ones in the back won't be a problem. The ones in front don't have very high levels, so neither will they.