From video:

From https://docs.google.com/do*ent/d/1NugtF12K5S1lPNH1vkE2cp5mjV9kEvJDLdaWFY_V610/edit (replace do*ment with doc-u-ment without -)

***How Skill Breakthrough Work***

Part 1

It’s real simple. As long as you have a 4 star version of a particular ninja, you get a skill book for that ninja and upgrade the corresponding skill. That’s it. There is a Skill Book for each character, and for each skill, and for each upgrade to a skill (e.g. Book to upgrade Itachi’s mystery from +1 to +2).

But Oppai, you ask. Where do I get these Skill Books? Well, young grasshopper… that’s something I don’t feel like explaining. Watch this video to see how it works (https://www.youtube.com/watch?v=x7XDAMJ0yEs&t=81s) and check this link to see the logistics (http://*.qq.com/wenda/share/38948). Use Google Translate, if you actually care.

Part 2 (Part Y)

The newer system introduces skill changes, where the skill is completely changed. This system works similarly to purifies, except for skills. You can buy items from the Redemption Market or the Shop (little test tube potion things), and other items to lock a skill in place. As you can imagine, this is pretty dern costly, especially depending the ninja.

When you refresh a skill tree, all of that character’s skills (that can be changed) will be shuffled between all possible upgrades and changes (from +1 to +2 to +Y to +2Y). This means that feasibly, you can access upgrades to skills you have not found the skill books for. This doesn’t mean skillbooks are completely obsolete, as skillbooks create a baseline under which the breakthrough cannot fall under e.g. if you have a +2 skill book, that skill, when reshuffling will not become +1. Furthermore, you can freely switch between a +1/+2 skill and a Y skill in the same tree if they are the same color. That means if you have fully breakthroughed a ninja, you can access its Y arsenal and mix and match freely without going through the “purify” B.S.

Part 3 (Part L)

This is just Part Y, as far as I’m concerned, but it’s slightly different, so I’ll put it in its own category. Currently, there are very few ninja that this applies to. This is different only because of 1 key factor. L skills come in pairs and consist of an upgrade AND a downgrade. Meaning, one skill gets an upgrade and another skill gets a downgrade. You’ll see when I show you get to those characters.

Other than that, the way of getting those skills is the same as Part Y.