Critical ability Critical abilities , also known as SOS abilities , are a set of recurring abilities in the series . First appearing as SOS Shell in " Final Fantasy V " , Critical abilities have grown to include just about all of the positive status effect es , and are only active so long as the user is in Critical . The Critical ability cannot be Dispel led while active , and will automatically reapply itself should the character be KO ' ed and revived back into Critical . The moment the user is restored to above their Critical HP limit , the ability will wear off . The following is a list of Critical abilities that have appeared throughout the series : While the following aren ' t named " Critical " , they still follow the same format : Appearances . " Final Fantasy IV " . Adrenaline and Last Stand appear in the Nintendo DS version of the game only as Augments . Adrenaline is received through Cid after modifying the " Falcon " and by giving him 2 Augments . Last Stand is received at the Tower of Zot , and if Tellah had been given 1 or more Augments . " Final Fantasy V " . Magic Shell , also known as Magiwall or Barrier , is the Level 1 ability of the Mystic Knight class . It requires 10 ABP to learn , and once mastered , will automatically activate Shell when in Critical if the character is a Freelancer . " Final Fantasy VI " . The Barrier Ring cast Shell while the Mythril Glove cast Protect on the user once they enter Critical status . The Princess Ring , a female - exclusive relic , casts both Protect and Shell when the user is Critical . There is a dummied ability that cast Reflect when the user came under the Critical status . These abilities will only activate once per battle . " Final Fantasy IX " . Restore HP support ability can be learned by the melee characters through the Brave Suit , Promist Ring , Platinum Helm , Grand Armor , and Minerva ' s Plate . " Final Fantasy X " . There are numerous SOS abilities in " Final Fantasy X " . The SOS Overdrive ability is an auto - ability for weapons . It is the SOS version of Double Overdrive , charging the Overdrive gauge at double the rate when the character ' s HP is HP Critical . It can be customized to a weapon with 20 Gambler ' s Spirit items . The SOS abilities for armor focus on granting a status to casters . Each of the four elements have their own respective SOS ability which provide completely immunity from an element when the character with the respective equipped armor via the Nul - statuses . Due to their functionality , they work like SOS versions of the elemental " proof " abilities . The SOS NulBlaze auto - ability grants the user the NulBlaze status , giving them full immunity to the Fire element as long as their HP is critical , and can be customized to an armor with a Bomb Core item . The SOS NulShock auto - ability grants the user the NulShock status , giving them full immunity to the Lightning element as long as their HP is critical , and can be customized to an armor with a Lightning Marble item . The SOS NulTide auto - ability grants the user the NulTide status , giving them full immunity to the Water element as long as their HP is critical , and can be customized to an armor with a Dragon Scale item . The SOS NulFrost auto - ability grants the user the NulFrost status , giving them full immunity to the Ice element as long as their HP is critical , and can be customized to an armor with an Arctic Wind item . The remainder of the SOS abilities for armor are all spiritual predecessors of a number of the abilities with an " Auto - " prefix . The SOS Shell auto - ability grants the user the Shell status as long as their HP is critical , and can be customized to an armor with eight Lunar Curtain items . The SOS Protect auto - ability grants the user the Protect status as long as their HP is critical , and can be customized to an armor with eight Light Curtain items . The SOS Reflect auto - ability grants the user the Reflect status as long as their HP is critical , and can be customized to an armor with eight Star Curtain items . The SOS Haste auto - ability grants the user the Haste status as long as their HP is critical , and can be customized to an armor with 20 Chocobo Feather items . The SOS Regen auto - ability grants the user the Regen status when their HP enters critical . Unlike other SOS abilities , it remains with the player after they have left the Critical status , however it becomes susceptible to Dispel . It can be customized to an an armor with 12 Healing Spring items . Customizing SOS Regen to armor is part of a Gil trick involving Kottos at the Monster Arena . " Final Fantasy X - 2 " . SOS Shell , Protect , Regen , Wall , Haste , Spellspring , and ? ? ? are the SOS abilities in " Final Fantasy X - 2 " . All but SOS ? ? ? can be found on various Dressphere s , while SOS ? ? ? is unique to the accessory Cat Nip . SOS Critical is unique to the Samurai , and costs 80 AP to master as well as having already learned Fireworks . SOS Shell is an ability of the Selene Guard Garment Grid . " Final Fantasy XII " . Adrenaline , Last Stand , and Spellbreaker are all Critical abilities found in " Final Fantasy XII " . which increase attack power , defense and spell power , respectively . Adrenaline and Spellbreaker take 65 LP to learn , while Last Stand takes 70 LP . The same effects can be gained via certain accessories . Gallantry and Chivalry are Critical abilities exclusive to Basch . " Final Fantasy XIII " . Critical : Protect , Shell , Veil , Bravery , Faith , Vigilance , Barfire , Barwater , Barfrost , Barthunder , Haste and Tetradefense are gained by equipping certain accessories . Critical : Shell is granted by the Auric Amulet . " Final Fantasy Tactics " . Critical : Recover HP , also known as HP Restore , is a reaction ability in " Final Fantasy Tactics " . The Monk class learns it for 500 JP . When a unit equipped with this ability suffers from critical loss of HP , the unit ' s health will be replenished automatically . Critical : Quick is a reaction ability in " Final Fantasy Tactics " . The Time Mage class learns it for 700 JP . When a character receives damage that reduces his / her HP to critical level , the character ' s AT will be elevated into the next position for immediate turn . This ability is the basis of the Quickening glitch , which allows player ' s characters to act infinitely . MP Restore is a reaction ability in " Final Fantasy Tactics " . The Summoner class learns it for 400 JP . If this unit is attacked and put into a critical state , this ability will activate , fully restoring the character ' s MP . " Final Fantasy Tactics Advance " . Last Berserk is learned from the Defender job for 300 AP , while Last Haste is learned for 300 AP from the Beastmaster , Ninja , and Mog Knight classes . Last Quicken is also learned for 300 AP , from the Time Mage . SOS abilities include Critical : Haste , Critical : Quicken , Critical : Vanish , Critical : Berserk , and Critical : Evasion↑ . " Dissidia Final Fantasy " . The abilities Magic Shield and Physical Shield activate when the character is at critical HP , and reduce magical and physical damage by 20 % , respectively . The Back to the Wall ability increases the chance of landing critical hits by 50 % when the character is at critical HP , while Cat Nip increases the chance by 50 % when the opponent has enough Bravery to kill the character in one hit . The Rebellious Soul carries the Bonecrusher ability , which increases the character ' s Bravery by 20 % of their max HP when they enter critical health . In " Dissidia 012 " only , the Fury of Qu ' bia accessory found only in the Labyrinth carries the same ability . " Dissidia 012 Final Fantasy " . The same ability returns in the sequel to " Dissidia Final Fantasy " .