Fervor of Battle is a tier 6 keystone ferocity mastery with 1 rank.
Abilities give fewer stacks.
Fervor of Battle is simply too good at what it does. It works great as a basic attacker’s best friend, letting those with attack speed quickly gain stacks. Currently, single target abilities grant stacks of Fervor as well - twice as many as a basic attack, to be precise. While abilities should count toward building Fervor, champions who work spellcasts into their attack cycles are overperforming in the race to full stacks. We’re maintaining Fervor of Battle as a great choice for attack speed lovers while leveling the playing field in the marksman mastery space.
STACKS PER ABILITY CAST :  ⇒ 1
Ferocity and Stormraider's buffed, Precision nerfed.
If you've played even a handful of games on patch 5.24, you probably learned the same thing we did - 8-10 Thunderlord's Decree per game is probably too many. Yet, no Thunderlord's changes. What gives?
While Thunderlord's Decree is the go-to mastery when you're looking to dominate your lane, we're leaving it as-is for a few reasons. First, we're looking to it as a 'goalpost' from which we balance the other keystones around. It's something you can easily play around, has a good amount of impact, and synergizes well with certain champion kits. Additionally, we're avoiding playing 'whack-a-mole' with the Keystones (ie: just nerfing whichever is best at any given moment). By recognizing TD's strength and matching others to it, we build a better ecosystem for Keystones where you're free to adapt your builds, rather than just playing champions that abuse the best mastery.
So how are we tipping the scales? Injecting some strength back into Ferocity's Keystones while reverting buffs to Precision should help balance things out, no matter how you seek to deal your damage. Toss in a pretty spicy update to Stormraider's Surge and you have a wealth of options at your disposal. It's still possible that Thunderlords is over-tuned after all this, but bringing the others more in line with the leader should help us gauge how big the discrepancy is, rather than just cutting down the top over and over again.
Fervor of Battle
DAMAGE ON-HIT : [1-8 (at levels 1-18)] ⇒ 1-14 (at levels 1-18)
MAXIMUM STACKS :  ⇒ 8
Feast cooldown up. Fervor of Battle slightly reworked, and Deathfire Touch’s damage effectiveness is down.
Ferocity is definitely living up to the hype for fighters and mages looking to stay in combat, but provides certain champions too much power relative to the rest of the cast. Fervor of Battle is now about stacking damage against champions specifically, and Deathfire Touch is more focused about consistent applications of damage.
Fervor of Battle
MINION STACKING Now only stacks on champion hits
ABILITY STACKING Using abilities no longer grant stacks of Fervor
MELEE MATTERS Melee attacks now grant double stacks of Fervor
SPELLING IT OUT Hitting an enemy champion with an ability grants 2 stacks (2 second cooldown)
FISTS OF FERVOR : Added a particle upon reaching max stacks
We're updating the mastery system to offer focused, high-impact choices rather than a slew of nuanced micro-math optimizations. Each tier of decisions now successively grows in importance, ending in your final 'keystone mastery' which fundamentally impacts how you play your champion.
Rather than just the 'Offense' tree, let's look at the types of bonuses Ferocity provides. This tree is all about getting into fights and staying there, scrapping with anyone at any time. Many of its bonuses help you against a large number of targets (attack speed and % penetration are pretty 'always good'), but bursty mages or assassins may find single target isolation somewhat lacking. Wanna deal damage, but worried about tanks and fighters getting in your face? Get ferocious and bite back.
Fervor of Battle
STACKTIVATE : Your basic attacks and spells give you stacks of Fervor for 5 seconds, stacking 10 times. Each stack of Fervor adds 1-8 bonus physical damage to your basic attacks against champions, based on your level.