Final Fantasy X has a rather unique character system that potentially allows any character in the game to learn any skill or spell in the game. Characters that are more naturally suited towards certain skills and spells are designed to learn those skills and spells more quickly, but if you play your cards right, any character can learn any skill or spell as easily, or sometimes even more easily, than the character designed to learn those abilities. All abilities are separated in four categories: white magic, black magic, skills, and special skills. White magic costs magic points to use and is primarily focused on healing and buffing your characters. With the exception of healing, most white magic requires you to be proactive, which means it is best used when you have a good understanding of what enemy you are fighting. The following guide to white magic in Final Fantasy X will help you decide which spells are worth getting and for which characters.
NulBlaze / NulShock / NulTide / NulFrost – These four spells are easily available to Yuna at the start of the game, though they are mostly a waste until you start regularly fighting boss battles. The incredibly low magic point cost of these spells means that they are effectively free to use, but they also don’t have a lot of value, either. If you want to save Ability Spheres early in the game, thus saving you some money, don’t bother learning them until just before a battle where you need one. This basically means you need to save just before any boss battle and restart if you lose, but it will save you gil early in the game when it is hard to come by.
Cure – Yuna has to back track a little to learn this spell, but if you don’t teach it to her, she is all but useless for the early part of the game. You will also be relying almost entirely on Rikku and her Use ability for healing if you go that route. If you are willing to abuse the Blitzball League, you should use Teleport Spheres and Return Spheres in order to teach this spell to all characters in your party.
Esuna – Arguably, this spell is even better than Cure. You can get by using Potions to heal your party, even if it is very expensive, but clearing status effects is much more difficult. Most items can only cure one status effect at a time, and you need to own the specific item for any given status effect. Esuna clears all status effects from a single ally. Yuna learns this from the start. While you are busy teleporting other characters to learn Cure, you might as well pick up this spell at the same time.
Life – Life is a quick spell for Yuna to learn and she should pick it up very early in the game. It is just far enough down her path that other characters should really bother trying to learn it when they teleport over to learn Cure, except maybe for Auron, and only because his skill path is weak enough that he basically makes a better second white magic user than anything else. If you have any White Magic Spheres, have at least one other character learn this. Tidus is the best choice because he is durable and quick.
Cura – The moment you learn this spell, you should never cast Cure again with any character that knows it. It heals much better than Cure does, at only twice the magic point cost. Yuna will learn it naturally, but it takes a while and no other character has an easy route to it. The spell is also on a point in the path that isn’t really near anything else, which means it isn’t worth the effort to teach it to other characters.
Curaga – Curaga is to Cura what Cura is to Cure. Yuna won’t get to this spell until the latter half of the game, but Rikku can get it to through a back door using a Level 2 Key Sphere, which is actually one of the better uses of that Key Sphere. The spell is close enough to Regen that it is worth using the teleport trick to teach this and Regen to a few other characters.
Shell / Protect – These two spells reduce the damage taken by spells and physical attacks, respectively. They are useful in the early and middle portions of the game, but don’t actually become critical until the later sections of the game. If you want to save Ability Spheres, you can skip teaching them to Yuna when she first moves past them and only pick them up later. Also, if you use the Key Sphere trick with Rikku for Curaga, it is worth teleporting past them completely to join Rikku in that section and get Curaga and Regen first.
Reflect – Reflect is an amazing spell if you have the right character setup and terrible otherwise. When you cast this on an ally, all spells cast on that ally are reflected back to the caster. This is great when fighting a spell caster, but can also prevent you from healing allies. If a few characters have the Use skill, you should be able to safely use this tactic. Also, if you use the trick with Rikku described under Curaga, Reflect is very near the unlocked sphere. You can teach this skill to Rikku and have Yuna teleport there and then pick up this skill and Dispel while marching towards Curaga and Regen.
Dispel – Dispel is the offensive version of Esuna. It removes all positive status effects from the enemy. It is very close to Reflect on the Sphere Grid and Rikku will basically automatically learn it if you unlock the Level 2 locked sphere that blocks Curaga. You generally only need one or two characters that know this spell, so there is no reason to teach it to Wakka or Lulu, despite how close they are to this area of the Sphere Grid.
Regen – Regen is practically critical during boss battles and all but useless otherwise. It heals the target every turn while it is active. The more characters that know this spell the better, since you want to put Regen on all of your characters as quickly as possible in any fight and replace it as quickly as possible when the duration ends or it is removed.
Full-Life – This spell is excruciatingly difficult to learn. It is found on an offshoot path of Rikku and requires two Level 4 Key Spheres and a Level 3 Key Sphere to reach. The spell is better than Life because it restores an ally to full health when revived from the dead, rather than half health. Of course, you need to somehow get to this spell first. The sphere cost is so high that it is generally better to use a Warp Sphere to get here. If you can manage to get any ally here, use White Magic Spheres and Teleport Spheres to teach every other character as well.
Auto-Life – Oddly, Auto-Life is easier to learn than Full-Life. You only need two Level 4 Key Spheres and the route starts near where Yuna starts on the Sphere Grid. This spell is effectively a Life spell that you cast before the character dies, since it automatically revives a character that has been killed. Like Full-Life, you really want every character to know this spell, but since you should have taught Cure to everyone early in the game, it isn’t as difficult to learn for other characters. A Return Sphere will be enough to learn this once you unlock the locked spheres.
Haste – Tidus learns this spell early in the game and it is amazing. Haste speeds up the acting character and stacks with itself. It is possible to get a character to act multiple times before an enemy. It is definitely worth using Level 1 Key Spheres to teach this spell to both Rikku and Lulu early in the game as well.
Slow / Slowga – Slow is the opposite of Haste and Slowga is the same except it affects all enemies instead of one. Both spells are reasonably far down the main path of Tidus and not particularly useful. It is usually better to cast Haste or Hastega, respectively. In fact, once Tidus learns Haste, he is better off exploring the routes of other characters than moving towards these spells.
Hastega – This spell is amazing and found even further down the path than Slowga. Alternatively, Yuna can unlock a backdoor to this spell with a Level 2 Key Sphere. This is generally the best way to learn this spell. Once she learns it, have both Tidus and Lulu teleport over and learn it as well.
Holy – Holy is the final step in the main path of Yuna. It is the highest single damage spell in the game, even eclipsing Flare, though it also comes with a prohibitive cost. It isn’t a terrible spell for Yuna, because damage is always useful, but it is actually better to teach it to Lulu with a White Magic Sphere or have her teleport to Curaga and then walk the rest of the path all the way to Holy.
Scan – The only character that can learn this spell without a Level 1 Key Sphere is Kimhari but thankfully Level 1 Key Spheres are easy to get. Tidus, Lulu, Rikku, and Wakka all have relatively easy access to this spell. Lulu is the best to pick it up, though it is good for any character. The information it gives you on enemies significantly eases the game and the spell is practically free to cast.