Staying true to their promise of a massive update, the Mid-Season Update for Teamfight Tactics has brought a series of significant changes to the game’s gameplay. Most notably, 9 champions including 3 Divine units, 3 Void units along with Sona, Kassadin, and Lux will be removed from Teamfight Tactics.

Of course, with the removal comes the addition of numerous new champions and brand-new traits and systems, totaling 14 units, which promise to change the game’s meta dramatically. The specific announcement was made by Riot Games late last night Vietnam time:
Champions Removed from the Game
Void: Kha’Zix, Cho’Gath, Vel’Koz. You can no longer overlook the enemy’s defensive stats.
Divine: Kai’Sa, Kayle, Miss Fortune. These powerful ladies deserve the title of legends, but they are so strong that sometimes your whole team means nothing.
Sona: Her cleansing ability is too powerful and offers no counterplay, which is why Riot had to remove her.
Kassadin: With stats, traits, and skills that are too perfect, he needs to return to oversee the Void creatures.
Lux: Riot will be adding many 3-cost champions and had to remove one to maintain the balance, unfortunately, the chosen one is Lux.

New Champions
Vayne – Cost 3, Trait: Cybernetic, Class: Marksman

Skill – Last Moment: Vayne focuses completely for 10 seconds, dashing away from her target, and on every 3rd attack afterward, she will become invisible while dashing and her first attack afterward will deal 180/200/240% damage.
Zed – Cost 2, Trait: Rebel, Class: Assassin

Skill – Scorn the Weak (Passive): Every 3 basic attacks, Zed will deal an additional 20/40/80 magic damage and steal 25/40/80% of the current damage of that target.
Riven – Cost 4, Trait: Time Warp, Class: Blademaster

Skill – Energy Slash: Riven dashes and gains a shield of 300/450/900, then slashes forward dealing 100/150/450 magic damage. On every 3rd use, she will leap into the air and unleash a wave of energy dealing 400/600/1800 magic damage (to make it easier to understand, it will be similar to the Triple Strike in League of Legends, except the first use will create a shield).
New Traits and Many New Champions
Battle Machine (combo milestones 2/4/6 champions)
Effect: After dealing or receiving damage 10 times, Battle Machine champions will activate an effect based on their current health. If the champion has over 50% health, deal 75/150/225 damage to the nearest enemy. If the champion has below 50% health, restore 75/150/225 health.

Illaoi: Cost 1, Class: Brawler
Nocturne: Cost 2, Class: Assassin
Kog’Maw: Cost 2, Class: Cannoneer
Cassiopeia: Cost 3, Class: Mystic
Viktor: Cost 4, Class: Sorcerer
Urgot: Cost 5, Class: Guardian.
Space Pilots

Effect: Reduces the energy cost of Space Pilot champions by 30.
Nautilus: Cost 2, Class: Vanguard
Bard: Cost 3, Class: Mystic
Gnar: Cost 4, Class: Brawler
Teemo: Cost 4, Class: Marksman.
Paragon

Effect: Converts all basic attacks of allies into magic damage (Janna’s special trait).
Janna: Cost 5, Trait: Star Guardian.
Other Changes
Traits – Systems
Time Warp: Buffed at 4 and 6 champions, added a combo of 8 champions.
Void: Now has a combo milestone of 2/4/6/8 instead of 3/6/9. Now all allied champions when defeated will empower Void champions instead of just those of this trait.
Pilot: Now when the Super Robot is destroyed, the separated Pilot champions will be in a damaged state, instead of full health as before.
Marksman: Now has a combo milestone of 2/4 champions.
Vanguard: Now has a combo milestone of 2/4/6 champions.
Champions
Ezreal: Now will reduce damage and energy used for skills to focus on versatility.
Syndra: If her orbs haven’t finished flying and the target has been defeated, the remaining orbs will attack the next target.
Jhin: Attack speed will increase with champion level, so 3-star Jhin is a real threat.

Aurelion Sol: The small ships of this flagship will now drain energy from the target.
Ekko: Uses skills earlier and attacks enemies under a certain number of basic attacks. This means that if the enemy has few champions remaining, he will hit them more times. Additionally, Ekko also slows the attack speed of the enemy he hits.

Items
Infinity Edge: Always grants the user 100% critical strike but deals less damage.
Rapid Firecannon: Your attacks will not miss…. ever again.
Archangel’s Staff replaced with Blue Buff: Whenever a skill is used, the champion’s maximum energy will be set back to 20.

Explosive Charge replaced with Battle Machine Shield: Grants the champion the effect of the Battle Machine trait.
Galaxies
Patch 10.12 will not add a new Galaxy but Riot is in the process of removing the Purple Nebula Galaxy.
Starting from patch 10.13, each patch will add and remove 1 Galaxy until the end of season 3.
Others
3-cost champions’ champion pool increased from 16 to 18.
When selling a champion, you will receive full money to upgrade that champion (for example, if you sell a 3-cost 2-star champion, you will receive 9 gold instead of 5 as before).
Neeko’s Help will now always work, regardless of whether the champion pool is depleted or not.

With so many changes like this, it seems that Teamfight Tactics will have a completely different meta in patch 10.12.