|Tier I||The first cell you open each stage does not break your chain.|
|Tier II||If the sum of your chain is greater than the max stage power, kill monsters before they can deal damage to you.|
|Tier III||[ 2 Charges] Double the length and value of your chain.|
|Unlock I||Unlock by creating a 15-turn chain on Normal or above.|
|Unlock II||Unlock by creating a 30-turn chain on Normal or above.|
|Unlock III||Unlock by creating a 50-turn chain on Normal or above.|
The marksman plays extraordinarily different from the base game and can essentially kill almost every single monster on the stage if you play off chains with a value of 1. The marksman is great at killing enemies but generally plays fairly slow if you want to maximize effectiveness. Most of the marksman's gameplay revolves around the 2nd passive ability with the mastery and 1 passive ability acting as padding. Anything that activates a penalty on mistake, a penalty on monster reveal, or a limitation on flagging will almost stop this mastery dead in its tracks. This is because its main gimmick is technically you constantly making mistakes, revealing monsters to kill them, and relying on the ability to over flag/flag empty cells.
Techniques: Building up chains
We can continue doing this until no safe cell are left which will maximize how many chains we'll get. You just have to make sure that you only open or chord cells that you know are the same value that your chain is. In this case, we'd end up with a value one chain with a sum of 5. This is mainly useful to know before you're chain's sum is greater than the max stage power.
Techniques: Keeping Your Chain When Killing
The core of this technique is that the value it uses to add to your chain is the one after the monster is killed. This mixed with chording allows for the ability to clear almost all of a board of monsters.
Here's another scenario...
Every time you do this it counts as a mistake and reveals a monster so be careful of doing this in the wrong stage. The goal is to eliminate exactly the amount of monsters that are needed to bring the cell we're chording down to the value of our chain so we can keep it and do this technique again immediately after.
Techniques: Value Reduction and Clearing Boards
Value 1 chains are the most effective at clearing the board if you can get over the threshold of the max stage power. Using the chording killing technique above you can essentially continue this for nearly the whole stage by constantly trying to reduce the 2s, 3s, and 4s down to 1s by specifically targeting the monsters that make them too big for you to kill them without losing your chain. You can always reduce something down to a 1 with the above technique but can never bring 1s up to 2s with it so you'll generally have more options building up value 1 chains. Lets use an example with a 4 we're trying to reduce down.
With the reduction technique, you can strategically widdle down numbers to be easily dealt with and kill monsters. You are generally going to be using the chording trick on 2 and 3 value cells since they're the easiest to kill enough monsters to have it be a 1 after the chord. You can't entirely clear a board with this technique but you are generally left with 3-6 cells at the end of the stage. This is VERY time-consuming.
Uses for your Mastery Ability
You don't get any bonus for having a ridiculously high chain so this ability is mostly useless apart from a few scenarios. The main one being if you don't have enough cells to start building up your chain again to above the max stage power. You get a chain going to about half power or slightly greater then use this to allow yourself to use the second passive ability again.