In the Innocence Seekers and Yume ni Aruku series, mana starvation (魔力飢餓, maryoku kiga) is a condition which can affect mages. This condition can arise if the mage uses too much mana, to the point of using up his/her entire mana reserve. In gameplay, this occurs whenever a character's MP is less than zero.
If a character's MP is less than zero, then his/her HP will be used to restore MP. As long as a character's MP remains negative, his/her HP will decrease by up to 20 per cent per turn to recover up to 20 per cent MP per turn (the amount of MP recovered is proportional to the amount of HP decreased; this method of recovery will not increase MP to above zero). If the character's HP is at or less than 20 per cent, and is not enough to increase his/her MP to zero, he/she will be incapacitated and the remaining HP is used to recover as many MP as possible. If, at any point, a character ends up having more than 100 per cent negative MP, he/she will be immediately incapacitated and cannot be revived via normal means.
To revive a character with negative MP, the amount of HP recovered must be enough to allow recovery of MP to zero. If the revival item/spell recovers sufficient HP, then some of the HP gained will be used to recover MP to zero (if the amount of HP is exactly that needed to recover MP to zero, then the character will be left with one HP and zero MP). If the revival item/spell does not recover sufficient HP, then it will fail and the state of the character will not change. The implication of this is if the character has more than 100 per cent negative MP, then he/she cannot be revived via normal means (and will not even recover at the end of the battle). One of the few exceptions to this is the Elixir; this rare item fully recovers both HP and MP of all characters, including incapacitated characters. Because it recovers MP in addition to HP, it can revive characters with more than 100 per cent negative MP. Casting Revive EX will also revive a character with more than 100 per cent negative MP, but it will leave the character with one HP and zero MP (as opposed to its normal effect, which is to revive the character with full HP).
The method used to revive incapacitated characters with mana starvation outside of battle varies between games. In Innocence Seekers: Akari of the Light, one visits a Zodiac Warriors or Puella clinic in Yaezora, Chiyohara, Tokyo or Fukuoka, or the LSNS Eternity infirmary to revive such characters for a fee.