As an Assassin this season, my burst takes 2-3 seconds to work. So if an ADC can kill me in around 3 auto-attacks, there's literally nothing I can do to stop him.
Mages I can outplay. Supports I can evade. Tanks I can ignore.
But a mid-late game Twitch, Jihn, or Vayne? I'm dead before I even touch him.
Last week I played Vel'Koz. Fizz missed his ult, his E got blocked by my Banshee's. He then oneshot me from full HP with Q+W+Lich Bane. I wasn't even on a squishy build. So sorry, but I don't feel sorry for you.
Given Assassins' earlier dominance I'm not all that offended. But that's just a personal stance, because fuck assassin players who think they need to one-shot everything.
The reality is that nobody should be bursting anything down nearly that quickly. Not ADCs, not assassins. Unfortunately, all 3 adcs you listed are designed to win the battle of damage-- Twitch is slow and steady until he can E six stacks, Vayne will always chop off 12% of your HP and Jhin is literally designed to crit upwards of 1000 on the reg.
Anyway, the game just needs to dial back items. They've been aggressively upgrading items all over the place and it's kind of crazy right now, but it'll calm down soon. Just gotta paint some happy little ADCs.
Yea, but earlier this season it was the other way around, assassins 2 shot everyone, you can't have it just your way and not allow it to go the other way from time to time. Not to mention assassins are not late game picks anymore and adc's are all building late game right now.
assassins are there to tip the balance, kill squishy supports with cc, or weak adc, makig it 5vs4 or 5vs3.
but what is more sad is being instakilled as mage assassin or adc by a tank 0.0
https://www.youtube.com/watch?v=jOFENQS-35c&feature=youtu.be
Clearly assassins are weak just look how fed and how much skill that rengar had to use to instantly kill me from stealth. lets see he was 3-11 so damn super fed and farmed up with his 110 cs and barely completed 2 items and boots. had maybe 1 passive stack since his kill was on jayce and the other was on me. so yea man assassins so weak i wonder what woulda happened if he was 11-3 with more than 2 completed items.
Oh wow. Really?
Twitch, Vayne and Jhin? Are you kidding me? You mention literally 3 late game hyper carries and still wonder you get one shot late game?
As an assassin it is your job to shut them down early and not allow them become late game monsters. Also all 3 of them put a timer on your game. If you feed them or let the game go over 25-35 minutes (depends on elo and ADC skill), it's pretty much gg.
And also it sounds like you don't watch when and how they use their abilities so you go in when they have all CDs up and then can kill you. Watch for flash, heal, ult and you should be good.
I'm calling pure bullshit. Show some damned video.
Unless it's a Draven. In which case, that's obvious. The question then is why you failed so horribly that you LET the Draven get to the point he can one-shot you? You're an assassin. Your singular purpose is to prevent ADCs from reaching late-game.
Ain't Assassin Kayn perceived weaker than Rhaast? If you're playing the new guy, can you really make that general statement using only a single example?
Lategame?
Yes, an ADC will kill a squishy target in 2-3 auto-attacks. That damage output is the very thing they are designed to do.
But you can get a defensive item, even on an assassin. For instance, new Thornmail works rather well:
Level 18 Assassin has around 85 base Armor. Thornmail + runes are 84 bonus Armor. Total, 169 Armor, or 140 against a Last Whisper Upgrade. For health, let's take 2k base, 250 from Thornmail, 250 from Edge of Night. Total, 2500 HP. EHP: 6725 / 6000 against physical damage.
Baseline ADC: 100 base AD, 0.650 base AS, 3% AS/lvl (51% @18), 2k HP. 15 AD and 17.5% AS from runes and masteries.
Build 1: 
390 AD, 1.58 AS: 750.75 Damage-per-attack, 1186.19 DPS
Build 2: 
325 AD, 1.52 AS: 786.5 DPA, 1195.48 DPS. On average, 352 magic damage every 4 attacks (guesstimate).
Build 3: 
380 AD, 1.39 AS: 665 DPA, 924.35 DPS
Build 4:
340 AD, 1.75 AS: 748 DPA, 1309 DPS. On average, 352 magic damage every 4 attacks (guesstimate).
Looking at these builds (and ignoring Shiv damage for now), the Thornmail-possessing assassin would survive, on average:
Build 1: 7.99 attacks, 5.21 seconds. Build 2: 7.63 attacks, 5.42 seconds. Build 3: 10.11 attacks, 8.46 seconds. Build 4: 8.99 attacks, 5.38 seconds.
Well, how about an utterly squishy assassin, then? Assuming he didn't build any Armor?
85 Armor base, 94 total (runes), 91 against LWU. 2250 HP (still has EoN). EHP: 4365 / 4297.5
Build 1: 5.99 attacks, 3.16 seconds. Build 2: 5.72 attacks, 3.29 seconds. Build 3: 6.56 attacks, 4.32 seconds. Build 4: 5.84 attacks, 2.86 seconds.
TL;DR: Build like a squishy, get popped like a squishy. Building a bit of Armor goes a long way to help your survival.
Supports are a huge part of the problem lol.
You're both glass cannons. What do you expect? You get to insta-gib people starting at lvl 6. The ADC gets to insta-gib everyone at 6 items.
When you all-in a fed Draven as a fed Zed, hit all of your abilities, and you die because he bursts you harder than you to him while sucking up your life force. feelsbadman*[zombie-nunu-bummed]*
