ALL healing reduction has been nerfed, including Ignite! Despite this, Chempunk Chainsword is actually still a super gold-efficient item thanks to its stats.
Additionally, you have to keep in mind that a healing-reduction item will always apply its effect, while with Ignite you may run into a fight where it's on cooldown.

So in short, it's better to go for a gold-efficient antiheal item + a mobility summoner spell ( Ghost or Flash) instead of time-gated antiheal + less mobility :)

Rhaast is meant to stay in fights for extended periods of time, relying on his constant healing to stay alive. You don't want to outdamage the enemy to kill them, you want to outlast them to secure the kill.

Based on how your champion is designed, there are going to be several instances during combat where you will drop below 60%HP, only to heal back up again. This is why Last Stand has a higher up-time for you than Coup de Grace, letting you proc it several times during a fight. Unless you are fighting against someone who also has a lot of healing, like Irelia or Fiora, your enemy will die once they fall below the 40%HP threshold that activates Coup de Grace. Only getting to proc this rune once in every encounter with a champion does not necessarily make it worth getting.

Does it just "feel" like you do less damage with the rune or did you track your games and check Rune damage done as well? Your playstyle may be influenced from how Shadow Assassin is meant to be played.

Only to be considered taking in high elo games. Low elo players are almost guaranteed to lack the coordination needed for following up on TP plays or utilizing them in different ways. You can test out Teleport in some Normal Games and see whether it works for you, but we do not recommend it for anyone below Masters rank.

Hi there, here's a quote from our Itemization section :)

GOREDRINKER AS A MYTHIC OPTION
This Mythic is an upgrade to one of your core items, Ironspike Whip . It is part of the "No Mythic" strategy that recently rose to popularity. The idea about this strategy is to only purchase the Mythic component Ironspike Whip and go for Legendary items afterwards. Other Mythic items don't offer you as much damage compared to the gold value you get from only building this component. Once you reach late game and have filled up all your other item slots you may choose between the following two options: Upgrading to Goredrinker , which is the go-to decision for most players, or replacing Ironspike Whip with an entirely different item. For the latter given scenario it doesn't matter what tier of item you purchase as long as it fits your games circumstances. It does not have to be a Mythic item.

We only recently updated the guide to showcase this build (me the main writer was lacking motivation, sorry) but can already confirm that it is basically the best one as of right now. Several high elo players advocate for it such as Karasmai and Rhaastafarian since you get to purchase all of your main damage items quicker.

Ironspike Whip basically functions the same as old Tiamat from Season 10 which made Blue Kayn really strong. Other Mythic items can't really compare in their gold value. You can get off some nice burst damage with Ironspike Whip's active effect by cancelling its animation with your Reaping Slash.

Once you reach late game and have filled up all your item slots you have the choice between finishing Goredrinker or getting an entirely different item. If you ever do want to build Mythic item then Prowler's Claw remains as an option.
It works well against a full squishy team.

Hi there! Apologies for the delayed response. In case you haven't found an answer to this yet, you can take a look at our FAQ section. The two questions listed there are basically the answer to yours:

Getting Shadow Assassin with Conqueror as your keystone is a strategy invented by Karasmai that many refer to as "bluser" (blue + bruiser). He tends to build regular Shadow Assassin items but occasionally throws in a Rhaast one such as Death's Dance.
However, the bluser strategy isn't recommended for players below Masters or even Challenger. The thing about high elo games is that they close out quickly, allowing you to not get punished late-game for not having the most optimal tools to do what you do best as Blue Kayn which is assassination, not dueling. What makes "bluser" good in high elo matches isn't his increased survivability but rather the early powerspike you get for not having to wait out your Darkin form. If are up against 2-3 tanks/bruisers, Rhaast will always be the best option and you should wait it out to get him as your form.