Note: This game is also titled Boku to Maou.
 

Hints & Tips

Easier experience
Continue after beating the first evil king (the rat). After beating second evil king (the fish-like creature), return to the place where the first evil king was at in the sewer. Once you get there, you will see bars that resemble those in a jail cell. Go near them and wait. A ghost will come after you. Let it get you for good experience. Then save and healer will also be close by.

Easier Sukel
In Tenel, proceed to the blacksmith's shop and talk to him. He will give you a Fruit Knife. Go to Madril and enter the shop. Talk to the kid at the counter and give him the knife. He will give you 300 Sukel.

When you obtain a new sword, sell your other weaker swords.

When you get though the Aquatic Ruins, you can keep going back to fight the earns to acquire more Sukel and experience.