Thresh, the Chain Warden is Riot Games' latest attempt at creating a new champion for League of Legends. The result is, as usual, a gimmicky overpowered addition to the game. Thresh is OP for two main reasons.
Thresh's passive allows him to collect souls dropped by slain minions. Each soul initially grants him something like +0.97 bonus ability power and armor. By the end of a standard game on Summoner's Rift, it isn't unusual to see Thresh with over 80 bonus armor and ability power (he also deals bonus basic attack damage based on souls collected but more on that later). Compare this to Graves who has a passive that grants him +10 armor and magic resist for each second he is in combat. While Graves' passive only works while he is in combat and then goes away, Thresh gets his huge bonus for the whole game. How's that fair?
To make up for this bonus, Thresh doesn't gain armor normally per level up. But let's compare Thresh with another "support" champion, Blitzcrank. Blitz gains +3.5 armor per level with a starting base armor of 14.5. That means at level 18, Blitz will have a total of 74 armor. As previously mentioned, Thresh can regularly achieve +80 armor from his passive alone. He starts with 18 armor, so by the end of the game, he's looking at a base armor of around 100 - far higher than Blitzcrank.
Let's compare Thresh to some other support champions. Taric has 16.5 base armor and gains +3.2 per level. At level 18, Taric has 70 armor. Nami has 9 base armor and gains +4 per level. At level 18, Nami has 77 armor. Soraka has 7.4 base armor and gains +3.8 per level. At level 18, Soraka has 72 armor. Notice how all of these champions end the game with very similar base armor stats? Why is it considered balanced that Thresh's would be so much higher than every other champion? Plus let's not forget his passive doesn't just give Thresh armor, either. He also gets bonus AP and base attack damage.
There is no getting around the fact that Death Sentence is an OP ability. Let's first compare the active ability to Blitzcrank's Rocket Grab because they are very similar pulls. Blitzcrank's Rocket Grab has a range of 925. Thresh's Death Sentence has a range of 1,075.
Rocket Grab stuns for 1 second. Death Sentence suppresses for 1.5 seconds.
Death Sentence also costs less mana to cast and has a smaller cool down.
In addition to all these perks, Death Sentence also has a passive bonus that Rocket Grab does not. Each of Thresh's basic attacks does bonus magic damage equal to the number of souls he has collected plus a percent of his AD (up to 80% / 110% / 140% / 170% / 200% AD).
Compare this to Master Yi's Wuju Style which grants him +15 / 20 / 25 / 30 / 35 attack damage per hit. By the end of the game Thresh is looking at +266 attack damage per hit (Thresh receives +200% of his AD as bonus damage per hit and has 83 base AD by level 18. 200% of 83 is 166. He also gets bonus damage equal to the number of souls harvested. Assuming he has 100 souls, that's another +100, thus +266). Keep in mind this is without any AD items.
So Master Yi gets +35 attack damage per hit (or +70 when activated) and Thresh gets +266. Not only is this ridiculously better than Yi's ability, it is simply the second part of an ability that is already strictly better than Blitzcrank's grab! How is this balanced?
Why is Death Sentence so much better than Rocket Grab and Master Yi's Wuju Style COMBINED? Some might point out that Thresh's ability has a wind up so it can be predicted and avoided. What about when Thresh is in the bushes and you can't see him winding up?
If you thought that Darius was overpowered, just wait until you lane against Thresh. His very presence makes the game progress at an extremely slow pace and not much fun to play.
Edit: Before anybody says I just suck at the game, I am 133/19/83 in my last 10 games.