Kayn vs Rhaast: First Impressions
So, I bought the Kayn bundle and have played him pretty much every chance I could since. I've gotten about 3 games on Shadow Assassin and 1 on Darkin, so what I say here is going to be a mix of my opinion and what I've noticed from a very small sample of games. That being said, what I'm going to say may not be entirely accurate, but I believe it's fairly accurate.
First, I'm going to talk about Kayn as a whole, then about Shadow Assassin form, giving my thoughts and opinions, and finally Darkin form, again with my thoughts and opinions.
Kayn is a very fun champion. He's a carry jungler who an be pretty decent in the right hands. His concept of permanent transformation is unique and it makes you actively choose who you're going to gank based on what you get from it towards your transformation, not just towards your team's goals.
However, that is a very dangerous playstyle, Say I want to be Shadow Assassin, but they have a melee mid laner, jungler, and top laner. I now am forced to gank bot lane, which is the highest risk and highest potential reward lane in the game to gank, in order to get Shadow Assassin.
If my ganks go successfully, we pick up an early dragon and maybe a turret first blood. If they go unsuccessfully, the enemy ADC is now fed and, depending on their pick, will now be very difficult for my bot lane to deal with, even if I come to try to help them again. It's safer to gank other lanes and accept getting Darkin form or wait the time after I unlock Darkin form to switch into Shadow Assassin instead.
But, let's talk about the advantages and disadvantages of each form.
Shadow Assassin: Pros: Increased mobility with the E giving you a larger movement speed boost and slow immunity More damage to enemy champions with his passive, as well as permanent bonus damage to jungle monsters, making his clear even stronger W becomes a very good poke tool with the extra range and the ability to move while it's casting
Cons: Ultimate's bonus (only resetting the bonus damage from his passive) feels lackluster compared to Darkin form No CC No inbuilt healing/survivability Weak to Tanks
Darkin: Pros: Tank shredder with % max health damage on Q and R High healing on Passive + R Knock up on W (synergy with Yasuo + hard CC)
Cons: Comparatively less mobility (though not by much) than Shadow Assassin Feels less smooth (can't move during W animation)
So, which is better?
Darkin, by far, is stronger than Shadow Assassin. My own personal opinion, though, I like using Shadow Assassin over Darkin because of how smooth the W Q combo feels. Definitely gonna try out a few more games as Darkin if I get him, though.
Also as a side note, I really hate how the Shadow Assassin looks with the skin. You look like a Red Mage from Final Fantasy, not a shadow assassin. Darkin form looks so much cooler, both with and without the skin.