Season 4 has ended and PreSeason 5 is here! Traditionally the preseason is the time of the year for big changes being made to League of Legends - be it items, masteries, runes or core mechanics of the game.
With big changes being imminent, we have analyzed 25,000,000 current mastery pages and looked at how frequently each single mastery is used.
Without further ado, we present the most and least used masteries of Season 4:

Most Used Masteries

1. Veteran's Scars   +12/24/36 Health

Ladies and gentlemen, this is it, the most-used mastery of this season! A whopping 74.2% of all mastery pages use this mastery, and 70.3% of all mastery pages max it by investing 3 points into it. Regardless of role and position, everyone wants a bite of the juicy Health it provides. It is worth noting that this is a Tier 2 mastery and it surpasses every single Tier 1 mastery. May we need an alternative Tier 2 mastery for the Defense Tree for the next season?

2. Block   Reduces incoming damage from champion basic attacks by 2

This is the most-skilled Tier 1 mastery. 67.8% of all mastery pages use this mastery and 53.6% max it. This mastery is a great way to reduce the poke you receive in the early game and opens up the way to Veteran's Scars, our #1 mastery of this season.

3. Juggernaut   +3% Maximum Health

This is the most-skilled Tier 3 mastery and a follow-up mastery to the number one: Veteran's Scars. 62.1% of all mastery pages contain this mastery, so there are more than 12% who use Veteran's Scars but don't use Juggernaut.

4. Executioner   Increases damage dealt to champions below 20/35/50% Health by 5%

This is the most popular non-Defense mastery of the Season. Executioner is a Tier 3 mastery of the Offense Tree and appears in 56.9% of all mastery pages; 53.1% max this mastery by spending 3 points on it. Regardless of whether you are a mage, an assassin or a marksman - it's hard to resist the powerful opportunity to deal an additional 5% damage to finish off a target that was cooked down in previous trades.

5. Sorcery   +1.25/2.5/3.75/5% Cooldown Reduction

With a total usage of 56.6%, this is the most-used Tier 1 mastery of the Offense Tree. Its 4 points are maxed by 45.4% of all mastery pages. This mastery was originally designed as alternative option for Fury (giving Attack Speed) and is not only picked by AP champions anymore - there are many bruisers, assassins and even marksmen who prefer a boost of 5% Cooldown Reduction over 5% Attack Speed.

Least Used Masteries

1. Vampirism   +1/2/3% Lifesteal and Spellvamp

This Tier 3 Utility mastery is the least used mastery of the season! Only 4.7% of all mastery pages use it, making it either a niche or a pretty useless mastery - that is up to you. Only a total of 3.6% max this mastery by spending 3 points on it. The main concern I see is the fact, that it is burried quite deep into Utility and nobody wants to dig through Tier 1 and 2 of the Utility tree, just to get some Lifesteal and Spellvamp.

2. Expanded Mind   +2/3.5/5% increased Maximum Mana

We're going one Tier deeper into the Utility Tree to find our next candidate: Expanded Mind is used by 4.9% of all mastery pages and maxed by 3.8% for a cost of 3 points. One reason for the unpopularity of this mastery might be the fact that increased Maximum Mana won't help you to stay on the lane for a long time. You might be able to bring out one more spell and that's it. The more clever way is to invest into Mana Regeneration which allows you to stay in the lane for much longer than with this minor boost to your Maximum Mana. There are only very few champions who can make an actual use out of Maximum Mana (e.g. Ryze or Blitzcrank), making this a very niche mastery.

3. Runic Blessing   Start the game with a 50 Health shield. This shield regenerates each time after respawning

Runic Blessing is one of the most-criticized masteries of the season, only appears in 5.1% of all mastery pages and can be found in Tier 5 of the Defense Tree. Note that it only grants a shield of a flat 50 Health which doesn't scale higher over time. Also, you only get it back after RESPAWNING, not everytime you go back to base. Hopefully we can see some changes to this mastery for the upcoming season. Maybe it could scale with the Max Health of the champion to make it a more reasonable choice for Health stacking tanks?

4. Inspiration   +5/10 Experience every 10 seconds while near a higher level allied champion

This Tier 4 mastery of the Utility Tree is very niche in itself as it can only possibly work on a lane with a fellow allied champion. Being burried deep in the Utility tree, this is only a valuable choice for Support champions. But that's not niche enough: It also requires your lane partner to be higher leveled than you in order to have any effect at all. The most-common use case for Inspiration might be a roaming supporter who roams to help out their Jungler or Mid-laner early, falling behind their marksman in level, and then return to their lane to utilize this mastery. Currently only 5.3% mastery pages use this mastery.

5. Reinforced Armor   Reduces the total damage taken from critical strikes by 10%

Reinforced Armor can be found in Tier 4 of the Defense Tree and is a follow-up to Hardiness. It is used by 6.1% of all mastery pages. The fact that this mastery only reduces damage from critical strikes, makes it very niche. While you probably wouldn't want to go with this mastery in Blind Pick mode, it might be a decent choice if you play a Tank on toplane and know that you are going to face an enemy like Yasuo or Gangplank (Yes, that is a champion!).

---

After all, what can I say about the state of masteries in general?
The Offensive Tree seems to be in a great shape and has many good options to choose from. Eventually it needs a few minor tweaks (e.g. nerf Executioner) but it looks good.
The biggest worry is the clearly underused Utility Tree. It just lacks some more attractive options to make it shine. Even supports often prefer to only partially go into the Utility Tree and find some goodies elswhere (popular Support mastery pages are usually 0/16/14, 9/12/9 or 0/9/21).
The Defense Tree on the other hand is very strong, and a wide majority of champions and roles like to put at least 9 points into it to get some bonus sustainability for the laning phase.

Altogether, there is some space for improvements in the mastery tree, and I'm looking forward to see the changes that may be coming to masteries for Season 5 in the coming weeks.