Mana

Mana is a resource used by the player when wielding Magic Weapons, the Magic Mirror, the Orb of Light, and the Dirt Rod. The player's current and maximum Mana is shown as a vertical meter of blue stars on the right side of the screen. Each character starts with no maximum mana, but that can be increased to a base cap of 200 (10 stars) by using Mana Crystals. After that it can further be increased past the cap by certain armors, accessories, and buffs up to a maximum of 480 (24 stars), in theory. In practice, Mana caps out at just 400 (20 stars)

Items that consume Mana
In addition to all items listed in Magic Weapons, using the following items also consumes Mana:

Increasing Mana
In order to use magic weapons more often, certain items can increase the maximum mana or reduce the cost of using magic weapons.

Restoring Mana
Mana regenerates on its own when not in use, until the player's current maximum, which occurs more quickly while standing still. The mana regeneration rate depends on the amount of mana you have left - it regenerates at a much faster rate when your mana bar is nearly full than when it is nearly empty. In this regard, it is usually not a good idea to use all your mana at once. There are also several items that can be used to regenerate mana. Notice that the last star on the Mana bar makes a pulsing motion.

Note that mana restoring effects will not exceed your maximum mana and any mana restore beyond the maximum is lost. It is advisable to avoid overusing of mana restoring items. Some of the mana restoring items share an item cooldown with each other and most other healing items. The cooldown is 60 seconds long and begins when the consumable item is used. During this period the player is not allowed to consume any more of those items. This prevents players from bypassing hazardous areas or enemies by constant item consumption.