League of Legends usually tries to make the game in a way that champions don't usually get to be strong in different timeframes of a match. Champions that are powerful during the early game rarely maintain that power for too long. And especially weak characters in the early game are usually given the opportunity to completely dominate once they have the needed levels and items.
Learning the nuance of early game characters countering late-game teams is an important step to fully understand the strategies and tactics applied in Summoner's Rift. Late game characters will eventually become too powerful, but some are quite easy to shut down.
10 Kog'Maw, The Mouth Of The Abyss
This champion is a feared creature of the Void. In order to understand his surroundings, Kog'Maw must drool on things. Unfortunately to whatever he is drooling on, his saliva is very caustic. This is not an evil creature, but it is destructive in nature.
Some champions have it especially hard due to their lack of mobility, defensive stats, or intimidating skills. Kog'Maw does not any of those in the early game. In fact, he is just an easy target with a short-range that is ready to be bullied.
9 Kayle, The Righteous
Kayle is the righteous warrior who is the daughter of a Targonian Aspect. Tired of humanity and their constant mistakes, she left the realm. However, many are those who share her legends and wait for her return. She is also a Champion that has one of the rarest skins in the game.
In the early game, Kayle does not have a lot of damage. Also, her passive has not scaled yet, and she does not have ranged attacks. Especially before getting her ult, she is an easy target who is easy to poke and bully. A lot of patience is needed alongside a careful playstyle to get Kayle where she needs to be for the late game.
8 Kassadin, The Void Walker
This champion saw his family be taken by the Abyss, making him decide to fight back. Kassadin uses forbidden technology and magical artifacts combined in a special way to grant him all the power he needs while he hunts down his enemies.
Although he is known for his burst damage and his low cooldown teleport, it takes a long time to get there. Kassadin won't start shining until level 11, and his true potential is only revealed at maximum level. Besides, before level 6, he is just an easy target.
7 Vayne, The Night Hunter
Shauna Vayne is a Demacian woman who hunts down monsters. She has sworn that one day she'd put down the demon who murdered her family. She wields crossbows and silver bolts when pursuing her targets.
She is never truly weak. Consecutive attacks from Vayne will kill anyone, even in the early game. Vayne's problem is the lane phase. Her ranged attacks do not have the greatest range. She also lacks a poking skill that won't put her in danger. Until she gets her ultimate, her escape is weak and her range is short, making her early levels hard to manage.
6 Azir, The Emperor Of The Sands
The reborn Emperor of Shurima, Azir was a mortal who recently returned to the world as an Ascended. Now, Azir is capable of conjuring soldiers of sand in order to fight for him in the Fields of Justice.
Azir can become one of the most destructive forces in League of Legends, but there is a trade-off. His early game is truly weak. He needs to level up to have all soldiers at his disposal, but he also needs a lot of gold. There are so many things that can go wrong for this champion during the early game.
5 Cho'Gath, The Terror Of The Void
As a perfect expression of the void, Cho'Gath's desire to consume life is never-ending. What makes him even more dangerous is how his body reacts to all the living things that he eats, always making him bigger and hungrier.
Cho'Gath is one of those champions who are not necessarily weak but have so many others who do his job better. However, before becoming the unstoppable, hulking, gigantic wall of Hit Points, Cho'Gath has to face newly created, highly mobile champions with more interesting and useful skills.
4 Twisted Fate, The Card Master
A bit like Gambit from X-Men, Twisted Fate is known throughout the whole world since there is no place where he has not gambled or charmed his way through. He is a bon vivant who never really takes anything seriously and seems to just live one day at a time.
When it comes to his early game, Twisted Fate is highly dependent on lower cooldowns and AP to make an impact. That means that his lane phase might be a huge pain for him. Also, since his ultimate is a utility one, he lacks the bursting potential that other mid-lane champions might have when facing him, making his life even harder.
3 Yuumi, The Magical Cat
The Magical Cat was the familiar of an enchantress. Since her master is nowhere to be seen, Yuumi decided to find the missing Yordle on her own. Meanwhile, she guards her master's sentient Book of Thresholds.
One of the most controversial champions in League of Legends, Yuumi has such a weak early game that many players might forget that she is there. The problem with Yuumi is that her weak gameplay might pay off later, but it does cause a lot of stress to the AD Carry that is paired with her. Especially in solo queues. When it gets to mid-game and beyond, Yuumi is very powerful. This is most likely why she is not one of the underrated support champions.
2 Yone, The Unforgotten
The murdered brother of Yasuo, the Ionian swordsman returns to the realm of the living. He wears a living mask and wields the word of a creature that attacked him after his death. Now, Yune hunts down creatures that threaten the spirit world while tries to understand what has happened to himself.
Yone can be easily poked and bullied by ranged champions in the mid-lane. His Mortal Steel will through him under the enemy when charged, unlike Yasuo's hurricane attack. His only way to poke is with Spirit Cleave but chances are, the other champion will have a longer reaching poke.
1 Karthus, The Deathsinger
This skeletal mage is an odd creature that is neither living nor dead. In fact, Karthus sees beauty in Undeath and the eternity that it brings. That must be the way he will emerge from the Shadow Isles from time to time bringing the joy of death to mortals.
Karthus becomes a powerhouse with a global ultimate that can take more than half of the target's HP right before a team fight starts. It is not one of the 10 best ultimates in the game, but still is one of the greatest. But to get there, there is a long path until max level with items. Karthus starts with low damage and weak stats. He also lacks mobility and burst damage.