Each one of your Chao's stats has a grade assigned to it, which indicates your Chao's natural skill and maximum potential in that area. From lowest to highest, the possible grades are E, D, C, B, A, and S.

When you level up one of your Chao's stats, its stat points will increase by an amount depending on your Chao's grade for that stat. This difference adds up significantly by the time you reach higher levels, meaning that a Chao with an S grade can end up with stat points for level 99 which are much, much higher than a Chao with an E grade. You therefore want your Chao's grades to be as high as possible.

Your first Chao will have its grades randomly assigned. A bred Chao will have its grades randomly chosen from the grades of its parents. A Chao that reincarnates will keep its previous grades. There is only one way to actually improve a Chao's grades, and that is through evolution. When your Chao has its first evolution, the grade associated with that type will increase by one rank, unless it is already at S. For example, a baby Chao with all-C grades that evolves into a Fly type will have its Fly grade increase to B, while the rest remain at C.

This means that you can raise one of your Chao's grades by one rank per life, making an all-S Chao a possible but lengthy task. When you are first starting out, it is recommended to first check your Chao's grades with the Chao Doctor, and then raise it into the type for which it has the highest grade. This will ensure that your Chao is very good at what it does.

How to make an SSSSS Chao

As you know from the explanation above, the best grade a Chao can have for one of its stats is S. This means that the best Chao would have S grades for all of its stats: S for Swim, S for Fly, S for Run, S for Power, and S for Stamina! This section will describe how to obtain an ultimate all-S Chao.

As previously covered, there is only one way to increase a Chao's grades, and that is through evolution. When your Chao reincarnates, it will keep its current grades. Grades are also inherited from parents when you breed Chao. These three facts present two methods of creating an all-S Chao:

  1. Evolution and reincarnation — Evolve your Chao over and over again to slowly increase its grades. For example, let's say you start off with an EEEEE Chao. If you evolve it into a Swim type, its grades will become DEEEE. When it reincarnates, it will become a baby Chao but keep its grades at DEEEE. You can then evolve it into a Swim type yet again to improve its grades to CEEEE. By repeating this process, you will eventually get an SEEEE Chao, and you can then start evolving it into the other types to improve those grades.
  2. Breeding — When you breed two Chao, the resulting baby will have its grades randomly chosen from the grades of its parents. This means that breeding can never get you a grade higher than you already have. However, it can allow you to combine multiple good grades and "breed out" any bad grades that you have. For example, let's say that you have two Chao: one with SSSEE grades, and the other with EEESS grades. When you breed the two together, you could end up with an EEEEE Chao if you're unlucky. However, if you are lucky, you might get an SSSSS Chao! You could also get anything in-between, such as SESEE or EESSE. The only way to get an all-S Chao from this method alone is to have an S grade in each stat from one of the two parents.

It is recommended that you start your quest for an all-S Chao by first looking through your current Chao to find the ones with the best grades. To speed up the process significantly, you should consider combining the two methods listed above. You can save a lot of time by using both techniques simultaneously!

For example, you can use the first method on two Chao with CCCCC grades. You could repeatedly evolve the first into a Swim type, and the second into a Fly type. Eventually, you will have an SCCCC Chao and a CSCCC Chao. You could then breed the two together until you get an SSCCC Chao — you could even do this multiple times! Then you can raise those SSCCC Chao into Run, Power, and Normal types, giving you SSSCC, SSCSS, and SSCCS Chao, which you can breed together for a new all-S Chao.

Once you have an all-S Chao, it is suggested that you consider making it a Chaos Chao. Chaos Chao can never die, reincarnate, or evolve, which means that their grades are locked forever. If you turn a Chao with bad grades into a Chaos Chao, then it will forever have bad grades. On the other hand, if you turn your amazing all-S Chao into a Chaos Chao, then this won't be a problem; additionally, you never have to worry about it dying and losing all your hard work! However, you should keep in mind that Chaos Chao cannot breed, so you should keep a regular Chao around with all-S grades for breeding new ones with.

How to max a Chao's stats

Obviously, to max all of a Chao's stats you will need an all-S Chao, right? That is correct, but it isn't the full story. Remember that when a Chao reincarnates, it retains 10% of its stat points. This means that you can keep increasing its stat points over many lives. However, you will eventually reach a limit.

So what is this limit? How high can a Chao's stats actually get? The short answer is that each stat (excluding the hidden Luck and Intelligence) can reach 3266 points. This answer will be explained in-depth below.

Consider a newborn SSSSS Chao (not a reincarnated one). It starts off with 0 points in each stat, with all stats at level 0. There are a maximum of 99 levels, and each level will raise the stats by 26-30 points for an S grade. Once it reaches level 99, the stat cannot increase any further.

So in order to get the best Chao, you will need to get 30 points at each level-up. This is where luck comes into play: the game randomly chooses which number (between 26 and 30) that it will increase by. Getting max stats is therefore extremely difficult, unless you reset every level-up until you get a 30 point increase.

Now for the in-depth mathematical calculations.

  1. A newborn SSSSS Chao that has increased by 30 points in every stat each level-up will have 2970 points when they all reach level 99. This was calculated as 30x99, as each stat starts at level 0 for a brand new Chao.
  2. When the Chao reincarnates, it will keep 10% of its stats and each level will be set to 1. This means that it will have 297 points in each stat after reincarnating, with each stat at level 1.
  3. On its second life, it can have 98 level-ups for each of its stats. If every stat increases by 30 points again each level-up, they will have increased by 2940 points (30x98). This means it will end up with 3237 points in each stat (297+2940).
  4. When the Chao reincarnates a second time, it will have 323 points in each stat. This is because the game takes 10% and then rounds the number down to the nearest 1. 10% of 3237 is 323.7, but it gets rounded down to 323.
  5. On its third life, it can again have 98 level-ups for each of its stats. By getting 30 points for each level-up, it will end up with 3263 points (323+2940).
  6. When the Chao reincarnates a third time, it will have 326 points in each stat. 10% of 3263 is 326.3, but it gets rounded down to 326.
  7. On its fourth life, it can again have 98 level-ups for each of its stats. By getting 30 points for each level-up, it will end up with 3266 points (326+2940).

Now, this is where it stops. The stat can never increase beyond 3266. Why? This is because the game always rounds down the decimal numbers to the nearest 1. When the Chao reincarnates, it keeps 10% of its current stat points. 10% of 3266 is 326.6, and that rounds down to 326. This is exactly the same number as it already started with, so it will never advance any further.

Of course, this all requires a 30 point increase in every single stat, every single level-up. This is incredibly difficult, and if you've done this then you are extremely lucky (by having the game actually do that for you!), very patient (by resetting the game so much), or a hacker/editor/cheater.