In the 10.12 update, Teamfight Tactics will undergo many significant changes, with 14 new champions directly impacting the meta. Therefore, players should invest some time to understand these new champions, as it will certainly be beneficial in the upcoming period.
Below is the power ranking of the 14 new champions on a scale from S to C (S+ being the highest):
Urgot – The Righteous Protector/Guardian (S+)

Urgot is the new 5-cost champion who is extremely bloodthirsty in the mid-season update. Somehow, Riot Games has given this champion such unreasonable power. The source of Urgot’s power lies in his ability, the Doomsday Drill, which pulls the furthest enemy within range and deals 2000 true damage (even the tankiest champions like Brawlers find it hard to survive), and even Guardian Angel won’t save the target. With just 1-2 energy items, Urgot can eliminate enemy team members as soon as the fight begins.
Notably, Urgot’s ability does not require any traits to increase its power, so he will undoubtedly replace Gangplank as the most dangerous champion of season 3.
Janna – Star Guardian/Mother of Light (A+)

With the ability to convert all physical damage from basic attacks into true damage (for Star Guardians) or magic damage (for other allies), Janna will become a surprise card when there are few players left. Because compositions with strong physical damage like Cannoneers, Marksmen, and Shadow Assassins suddenly turning into magic damage will completely collapse against teams without Mystics.
Viktor – The Righteous Protector/Wizard (S-)

Viktor will be the extremely imba replacement for Miss Fortune in the near future. His skill deals damage based on both % health and regular stats, and he doesn’t need to stand still like Miss Fortune, so he won’t fear being interrupted. Among the 4-cost champions, Viktor will have the highest damage skill.
Riven – Time Traveler/Blademaster (A+)

This champion will be a Blademaster + Time Traveler tank that can even be stronger than Shen due to her extremely annoying skill. Only costing 25 energy for one skill use, Riven can shield herself while dealing both single-target and AoE magic damage. Whether activating Time Traveler or Blademaster, she is still incredibly strong.
Bard – Cosmic Explorer/Mystic (S-)

Alongside the Gold Hacker, Bard will soon become famous for his “level hack” ability. Each time he uses his skill, Bard will create a small spirit in the bench, each spirit can be sold for 1 experience point.
According to the new mechanism of Teamfight Tactics in patch 10.12, selling champions will not incur a loss, so there will definitely be many players buying Bard to level up quickly. Besides the “level hack” ability, Bard can also activate Mystics very effectively in the early game.
Gnar – Cosmic Explorer/Brawler (A)

Gnar retains his skill from season 1 of TFT, and essentially, he is still a tank with a wide area knock-up as before. He can create powerful combos when combined with other champions that deal AoE damage.
Vayne – Super Technology/Marksman (A)

Vayne is the perfect savior for Super Technology, as now you don’t need to rely on luck to roll Ekko to get 6 Super Technology champions anymore. Additionally, Vayne is a rather unique Marksman who has the skill to both stealth and move, preventing being caught by Assassins in the backline.
Cassiopeia – The Righteous Protector/Mystic (A)

As a unique Mystic champion with damage-dealing skills, Cassiopeia is especially countering champions like Riven, Malphite, and Guardians, as her skill can reduce shield effectiveness by 50%. Plus, only costing 25 energy for one skill use, Cassiopeia can spam her skills continuously if equipped with energy items like Blue Buff.
Teemo – Cosmic Explorer/Marksman (A-)

If activated as a Cosmic Explorer, Teemo can spam his skills quite strongly; however, this 4-cost champion is still rated low because he only uses his skill on the nearest enemy champions (usually tanks). But this skill usage mechanism makes Teemo especially strong against Assassins, as all Assassin champions are now melee, making his slow from mushrooms quite useful.
Zed – Rebel/Assassin (B+)

Instead of having a burst damage skill like other Assassins, Zed has a passive skill that increases his damage every 3 attacks, so the longer he fights, the stronger he becomes. His damage output depends on how long he can survive.
Kog’Maw – The Righteous Protector/Cannoneer (A-)

With the ability to deal burst damage thanks to a 90% attack speed increase and dealing magic damage based on the target’s % health, Kog’Maw will compensate for the lack of magic damage in the Cannoneer composition.
Nautilus – Cosmic Explorer/Frontline (A+)

As a tank with a wide area stun skill lasting up to 3 seconds (halving the time against secondary targets), Nautilus will be a super popular tank because now with many Mystic champions available, he can combine with Frontline very early.
Illaoi – The Righteous Protector/Brawler (B+)

Although he has a quite powerful skill for tanking by stealing armor and magic resist from enemies, he is still quite weak because he is a… 1-cost champion. Only worth playing when reaching 3 stars or when playing a Righteous Protector composition.
Nocturne – The Righteous Protector/Assassin (A-)

As an Assassin with a stunning skill, Nocturne has extremely strong crowd control capabilities against backline carries. He is a solid pick to hold enemies in the Righteous Protector composition while waiting for Urgot’s cooldown to finish.