Easy "5k Monsters" achievement
In the desert level, you can get an Apprentice to over level 200 by taking advantage of the "level up" special. Have a party composed of an Apprentice, Priest, and Tank/Warrior/Paladin. Reroll if you do not get a Shield as a shop selection. Also have a combination of Healer and Alchemist pet ready. The Healer will be used for emergencies and the Alchemist to take advantage of the large amount of healing done by red potions at later HP levels. Play the desert level as usual by keeping your Apprentice's damage limited to 1 while raising HP to 30 to 50, increasing all defenses to 30+ (with Dodge higher), Luck between 30 and 40, health into the hundreds, then working on either physical or magical damage (in order) as well as speed between 50 and 60. After a certain point you can allow the other two characters to die. Keep using the Alchemist to make red potions to regain large amounts of health. Before reaching the final wave and Boss, make sure you have a set of four red potions. At the Boss, keep killing the other enemies to farm kills and level up (while still increasing speed and damage). Keep farming kills until you run out of potions. When you are just about to die, kill the Boss or be killed.
Easy "An Hour in Stance" achievement
Enter a battle and press two after you have an ally that is not facing an enemy. Allow the game to idle for an hour, then opt out of the battle. Note: You must either win, lose, or opt out of the fight to mark that time as being spent in a battle.
Easy "5k Monsters" achievement...