PROS + Very strong early + Good engage and disengage tools + You will have a lot of agency + Very fun to play Thresh has always been present in the support meta and the reason for this is that his kit is flexible and allows multiple different playstyles. If you want to play a support champion that can save teammates, lock down single targets very effectively or control multiple enemies with a 5-man Flay then you should consider learning to play Thresh.

CONS - Very skill dependant - Will struggle with weak adc - Has no sustain - Gets outscaled by enchanters Thresh has a very high skill ceiling. This means that you will need to spend a lot of time learning his kit to be able to pilot him effectively. You also have no sustain in lane so if you're playing against a long range lane it can be difficult to get any action going in the botlane especially if you can't access the bushes.

GUARDIAN Great into most matchups.

AFTERSHOCK Necessary against engage support.

GLACIAL AUGMENT Fine vs double ranged or dive.

Guardian is great against most matchups as you can fairly easily decide when to proc it as you're ranged and can more easily space with your Adc so it won't get wasted, you can also proc it with your Dark Passage from range. Aftershock is necessary against engage matchups such as Leona or Nautilus as it will allow you to facetank their engage and create space for your Adc. It will also help in later fights to make sure you don't get oneshot as easily. If you're the only tank/frontline on your team you need it even more. Glacial Augment helps in double ranged matchups as you make it harder for them to run away from you when you engage on them and also against dive comps as it will make it easier for your carries to kite them when they're slowed.

RESOLVE

Guardian is really effective as it will help you protect a single teammate more and you can easily use it with your Dark Passage from long range. Aftershock makes you tankier after you immobilize an opponent, which will allow you to buy more space in front of your team or in lane vs another engage support.

Font of Life gives your team slightly more sustain whenever you CC an opponent.

Bone Plating reduces damage taken in a quick trade, but against a botlane that can easily proc it on you without putting themselves in too much danger then Second Wind gives you more sustain against the poke matchups.

Currently I think Unflinching gives too little resists (at only 2-10) and Overgrowth takes too long to really have any value which is why I prefer going Revitalize now, especially if I'm going Guardian, Locket of the Iron Solari and maybe even Redemption.

INSPIRATION

Biscuit Delivery is going to give you some mana and health sustain which will help Thresh in the early game. Cosmic Insight gives you summoner spell and item haste which allows for more aggression. Hextech Flashtraption is also a good option for catching your enemies off guard.

Your rune shards are going to change depending on how you prefer to play. Personally I like going Ability Haste, Health Scaling and Flat Health. But if you like going Mobility Boots and Trailblazer then you can also consider taking Movement Speed.

INSPIRATION

Glacial Augment allows you to catch people even easier thanks to the slow and it also works really well defensively as it reduces damage to your teammates by 15% from those affected.

Hextech Flashtraption can catch your enemy off guard and lead to more picks.

Biscuit Delivery will keep you healthier and gives you a lot of mana in a pinch in the early game which is when Thresh wants to fight. Use the biscuits when you have low mana to get the most value from them.

Cosmic Insight will give your summoner spells more haste which will enable more aggression, but also gives item haste in case you're running Locket of the Iron Solari or Redemption.

RESOLVE

Font of Life gives your teammates extra sustain (also gets applied by Glacial Augment. Then choose Second Wind if you're going to get poked early game or Bone Plating against engage supports.

Your rune shards are going to change depending on how you prefer to play. Personally I like going Ability Haste, Health Scaling and Flat Health. But if you like going Mobility Boots and Trailblazer then you can also consider taking Movement Speed.

Great defensive item Locket of the Iron solari is still a fantastic item that helps you protect your teammates. This is just a fantastic item that should always be at the back of your mind.

Chivalry isn't dead Knight's Vow is tailor-made for Thresh, it gives you great stats for the cost and helps you peel for your fed teammate and keep them alive (and get some healing for yourself as well).

Speedy roams Trailblazer is a great item as it gives you and your teammates movespeed to cross the map faster. However as Thresh is considered a ranged champion he will not slow the enemy when fully charged, but it's still a great item.

Stickiness Zeke's Convergence has been changed once again. Now it creates a slowing field around you which makes you sticker and harder to kite away from.

Big teamfight heal Redemption is a great teamfight item, it helps in keeping your entire team alive during a fight. Don't be afraid of using it before a fight if you're about to take an objective.

Anti AD item Frozen heart is now a really cheap tank item that gives Thresh what he wants. Armor, haste and even mana are all good stats on him and the added benefits of the passives make this a really compelling item when facing multple AD or AA based champions.

Anti AP item Abyssal mask gives you a lot of magic resist and health for its cost. It also enables your ap damage dealers to do more damage.

Anti hard CC item Mikael's Blessing gives you more oppurtunities to peel your team if the enemy has some hard hitting CC spells e.g Enchanted Crystal Arrow or Sleepy Trouble Bubble.

Single damage threat Anathema's Chains is a decent choice if the enemy has one super strong member and four bots/tanks. It reduces their damage to you and also reduces their tenacity.

Great objective vision control Vigilant Wardstone should always be your final item if you get this far. It gives you more wards on the map, more control wards in your inventory and some nice bonus stats as well.

Passive: Damnation Full Ability Description Innate: Thresh's armor does not increase through growth (per level). Innate: Champions, large minions and large monsters that die near Thresh drop a Soul for 8 seconds. Epic monsters drop 2 Souls while lesser minions and monsters have a 33.3% chance to drop a Soul. Thresh automatically collects Souls near him or a placed Dark Passage. Soul: For each stack, Thresh gains 1 ability power and 1 bonus armor. Thresh doesn't gain any Armor per level, in return enemies dying near him periodically drop souls for him to pick up each giving him 1 AP and 1 Armor. General tips ✦Each soul has a gold value of 40 gold so don't underestimate them. ✦You can use your Dark Passage to pick up souls from a safe distance, beware of wasting the CD if you might get ganked though. Q: Death Sentence Full Ability Description Active: Thresh throws out his scythe in the target direction, becoming unable to move or attack while it is in flight. The scythe catches the first enemy hit to deal magic damage, stun and reveal them for 1.5 seconds, as well as reduce Death Sentence's current cooldown by 2 seconds. Thresh will also mark the target Shackled for 1.5 seconds, during which he is unable to declare basic attacks, and is slowed by 20% for 1 second. While the target is stunned, Thresh tugs twice over 0.8 seconds, pulling the target a short distance with each tug. After 0.5 seconds of hitting an enemy or instantly after hitting a minion or monster, Thresh can recast the ability while the target is Shackled, which will cause him to stop tugging. Recast - Deathly Leap: Thresh dashes to the Shackled enemy, becoming able to attack again upon arrival. He can cast Dark Passage and Flay during the dash. Thresh's most iconic spell, the hook. Used for making picks and peeling scary threats off of your carries. Lowers the cooldown whenever you hit an enemy. When you hit an enemy you tug them in twice before letting them go, but you can recast your Death Sentence to dash towards them. General tips ✦If your enemy has Cleanse you should hold your Ignite until after they Cleanse your Death Sentence. This way they don't Cleanse two things at once. ✦Try to pay attention to where the enemy wants to dodge and try to learn the dodging patterns of your enemies. If you notice that the enemy Adc doesn't dodge, but the Support dodges to the left keep that in mind for when you aim the skillshot. W: Dark Passage Full Ability Description Active: Thresh throws his lantern to the target location over 0.5 seconds, lasting for 6 seconds while he remains nearby and granting sight of its surroundings. If Thresh moves too far away from the lantern, it returns back to him immediately. Thresh and the first allied champion to come near the lantern are granted a shield for 4 seconds. An ally can select the lantern while in proximity of it, dashing to Thresh and gaining the shield. An ally cannot select the lantern while immobilized, grounded, or silenced. The lantern will not expire from Thresh moving too far away if he is dashing with Deathly Leap. Probably Thresh's most powerful spell. Can be used to very easily reposition your teammates either for the purposes of peel or for followup on your engage. Also gives a shield that scales off of your souls from Damnation. General tips ✦Place the Dark Passage in the direction your teammate is running. This makes it easier for them to click it and harder for the enemy to block it with a ward. ✦You can use your Dark Passage to check bushes or over walls instead of facechecking. ✦Your Guardian will be active on a teammate when you shield them with Dark Passage from range. E: Flay Full Ability Description Passive: Thresh's basic attacks are empowered to deal bonus magic damage, with the AD ratio increasing over 10 seconds without basic attacking enemies. Active: Thresh sweeps his chain across the ground in a broad line and a radius around him, starting behind him and towards the target direction. Enemies hit are dealt magic damage and knocked 200 units in the target direction, and then are slowed for 1 second. An incredible tool that will separate the good Thresh players and the great ones. Can be used as a simple knockback for peel or to lock people down for longer or you can utilize it further by cancelling dashes such as Rocket Jump or Elastic Slingshot. It also has a passive that makes your AAs deal more magic damage based on your souls and total AD. General tips ✦If you're playing against a short range botlane you can put one or two more points into Flay and maybe take an extra Adaptive Force so your AA will do some more damage. ✦Hold your Flay for just after your Death Sentence ends against certain champions like Kha'Zix, this way you are more likely to cancel their escape ability which they are most likely spamming while they're CCed. R: The Box Full Ability Description Active: Thresh erects a pentagon of spectral walls around him that each last for 5 seconds. A wall will break upon enemy champion contact, dealing magic damage and slowing them by 99% for 2 seconds. Enemies that break a wall cannot do so again for 1 second. Subsequent walls they break will deal no damage and slow for only 1 second. Thresh summons a pentagon which damages and slows the first enemy hit. Subsequent enemies just gets slowed for half of the duration instead. Can be used to either help burst a squishy target during your CC or to dissuade the enemy from chasing you further. General tips ✦After you hit a Death Sentence you can immediately cast The Box during the CC and then Flay the enemy into one of the walls for a massive slow and a decent chunk of damage on a squishy target.

With the new season comes a lot of changes to the rift and builds, but I'll try to keep this chapter concise and relevant to Thresh.

Firstly our support item got merged into just one with multiple choices as the quest reward. The two best ones are Solstice Sleigh which will give an ally more health and movespeed great for both engaging and disengaging fights and Celestial Opposition which is great for both defensiveness against divers or assassins, but also great if you want to be the initial engage for your team. Bloodsong is a bit more of a for fun choice, but as Thresh is ranged and doesn't really proc the effect easily in his combo it doesn't give as much value as the other options.
The support item no longer has Attack Damage or Ablity Power which means that your Adaptive Force from runes will only be AD unless you build AP e.g Shurelya's Battlesong as the AP from your passive Damnation will not change the Adaptive Force to AP.

Mythics have been removed so Evenshroud is gone and Shurelya's Battlesong has been changed so it's no longer a good item on Thresh.

Unflinching has been changed to not give tenacity anymore. Now it only gives a very small amount of armor and magic resistance when you've been CCed. I think the numbers on it needs to be buffed for it to be considered a good rune.

This chapter will have random information and tips regarding that didn't fit into the guide elsewhere.

Runes:

Taking Revitalize may look odd on Thresh as he only has a weak shield on his Dark Passage, but it will also buff your Guardian, Font of Life, Second Wind, Locket of the Iron Solari and your Redemption. The small 5% heal and shield power (+10% strength on targets below 40%hp) may not look like a lot but it will add up over the course of a game.

Assuming you don't miss a single minion death then Overgrowth will give you the 3.5% bonus max health on the wave that arrives in lane at 10:30. At that point the other part of Overgrowth gives you 45 HP. At this point Damnation will have dropped around 42 souls giving you 42 armor and AP. Needless to say that in a real game you will be missing some minions either from roaming, recalling or being forced off the wave so realistically this rune will take longer to come online.

Health Scaling vs Flat Health in the bottom row of rune shards? Generally scaling shards are worse on supports as we get less XP than other roles and we need to fight early especially on Thresh. So I would recommend taking Flat Health, however sometimes you can be greedy and take the Health Scaling. Generally if you need tenacity you're better off just buying Mercury's Treads instead of taking the Tenacity and Slow Resist rune shard.

Items:

The damage taken from Knight's Vow when redirected from your ally to you will proc and "waste" your Celestial Opposition so try to keep that in mind as you have to be out of combat for 18 seconds for the shield to come back up. It also deactivates your Mobility Boots even if the damage is only from minions.

When in a fight without your Knight's Vow target (whether they're dead or just not in the fight) you should try to change your mark to another teammate. This way you're still getting value from the passive. Another thing to remember is that the target doesn't have to be your adc. If your adc is super behind while your midlaner is smurfing you should change priorities. Don't get stuck in the mindset of having to support only your adc!

Solstice Sleigh is not a heal it only gives bonus health, so it is not affected by grievous wounds or heal and shield power. Think of it as a mini Wild Growth.

If you finish your support quest and are starting to have regrets over your choice of item (whether you missclicked the wrong item or think another item will have more value) you can sell your Solstice Sleigh and buy Celestial Opposition from the shop. This does cost you 240 gold because you only get 160 gold from selling your item and it costs 400 to buy it again so it's not super ideal, but it is good to know for those awkward times when you accidentally click the wrong one or get into a really long game. Generally I'd say that Solstice Sleigh gets outscaled by Celestial Opposition.

Abilities:

Generally starting with Flay is best as it gives you more power and allows for both proactive trades and defensive peel, however when playing against a double ranged botlane I like starting Death Sentence as it gives me the opportunity to catch the enemy off guard level 1.

When you hit a Death Sentence on someone don't immediately use Flay. Instead wait for your Death Sentence to tug them in twice and then Flay them right after your Death Sentence ends. This way you can CC them for longer and potentially cancel their dash/jump with your Flay. Most people will be spamming their escape button during your Death Sentence so this way you will be more likely to cancel their Rocket Jump for example. If you're struggling with the timing then spend a few minutes in Practice Tool and you can get it down pretty fast.

I've experimented with going Ingenious Hunter for Locket of the Iron Solari and Redemption before, but I decided it probably wasn't worth it (despite it reducing the cooldown by 30 seconds when fully stacked). However now with the support items Solstice Sleigh and Celestial Opposition there is even more value with going Ingenious Hunter so I'll start experimenting with it again. The main drawback is that we're losing the summoner spell haste from Cosmic Insight and early sustain from Biscuit Delivery.
I'd also like to get Redemption right away as my second item which means I'm probably not going to get Knight's Vow unless the game goes very long which will make me and my primary carry even squishier.
Alternative would be Relentless Hunter with Trailblazer and Movement Speed rune shard for fast map movement if the game is going to be chaotic.

Check out my other guides if you'd like!

Embrace the depths
Warm hugs for everybody!

Special thanks to jhoijhoi for their great guide to coding.