As your party explores the pages of the Roguebook, uncovering each hex and risk the wrath of any monsters that hide there, you will notice that your party is taking a lot of damage. This can’t be allowed to build up, as the run comes to an end when your characters run out of health.
If you want to make it deep in to the book, you are going to need to find ways to heal.
The most obvious way to heal is by finding Radiant Hearts while exploring the map. These will restore 10 health to each character in the party. As such, you should make sure you are only using them when you will get the full benefit. You can always save the Radiant Heart and use it before a big fight after both characters have lost 10 points of health each. They can also stack, so make sure you pick up each one you pass.
One of the characters in the game, Seifer, can self heal through doing damage. This is a great ability, and makes the character essential in your parties.
Items and Upgrades
Some items will give characters healing after battle, or after they inflict damage on other characters. Think carefully about what you are doing with each character when assigning items. Your normally want healing items to end up on characters that are out front, tanking incoming damage, but if an item gives a certain amount of healing return for damage that you cause, you will want to put this item on a damage dealing character.