Greetings! I am a really inexperienced guide maker, so please pardon the errors I have made (oh also English isn't my first lang so sorry for the grammatical errors)

I am a Kayn player that is currently not playing Kayn but will play in about 10 hours this guide was made so do not worry about this moron not even playing Kayn but making a guide!

I just love playing as him but Rhaast is just a bit of kill or get killed if you are trying to make the "sick playZ" he heals a ***** ton of health thanks to his passive as for The Edgy Teen... Well, he is good but certainly, **** against tanks with over 3k HP or maybe lower? Who knows really. Enough of this introduction! I will now give you info about their abilities.

Passive:

Shadow Assasin or Rhaast
Kayn is wielding an ancient, sentient weapon Rhaast that battles him to gain control of him. If you damage -or- kill a melee champion you'll help Rhaast reach his goal of controlling him but if you damage -or- kill a ranged champion you'll help Kayn defeat Rhaast.

Shadow Assasin deals 12% - 44% magic damage for the first 3 seconds of a fight refreshes after 8 seconds or after using his ultimate

Rhaast heals for 34.5% - 43% of the damage he deals to champions with abilities

Reaping Slash:

As Kayn and Shadow Assasin you dash forward and do Yasuo's E+Q both of the dash and spin deals damage

As Rhaast you'll deal + 5% (+ 4% per 100 bonus AD) of target's maximum health as physical damage with both the dash and spin. -also, heal yourself if you use it on a champion-

This is why Rhaast is a tank buster.

Blade's Reach:

As Kayn you perform an upwards sweep with your scythe dealing physical damage and slowing enemies by 60% for 1,5 seconds.

-he can't perform any other actions while casting-

As Shadow Assasin Blade's Reach' range is increased by 200 additionally you can move during the cast and freely do anything.

As Rhaast Blade's Reach knocks enemies for 1 second.

Shadow Step:

As Kayn and Rhaast you ignore terrain collision, gain 40% bonus MS, become ghosted and heal if you move into a wall.

As Shadow Assasin you remove all slows and make yourself immune to all slows for the duration additionally you'll increase your MS by 70% if you move into a wall.

Umbral Trespass:

Passive: Whenever Kayn damages an enemy champion, he applies Umbral Trespass for 3.5 seconds.
As Kayn you will infest the marked enemy champion for up to 2.5 seconds gaining true sight on them and becoming untargetable for the duration

you can end the ult quickly if you activate it again

As Shadow Assasin Umbral Trespass gains 200 Range and resets the passive of Darkin Scythe

As Rhaast you deal 10% (+ 13% per 100 bonus AD) of target's maximum health as physical damage and heals you for 7% (+ 9.1% per 100 bonus AD) of target's maximum health.

For Rhaast:

1st recommendation

2nd recommendation

For Shadow Assasin:

Classic.

If you insist on playing Shadow Assasin against 1 tank or like 2 bruisers with armor? Then this is what you are looking for. It can be used in every situation though!

We start at raptors if we are going to quickly do a full clear

We start at bot side if we are going to level 3 gank top

YOUR CLEAR IS GODLY

So you should be quickly ganking and contesting scuttles! Don't waste your time "***in aroun" and gank after your first full clear or even if you see an opportunity because you have really good ganking with that E of yours

YOU NEED TO HIT THE W ITS YOUR ONLY CC

Try to get the drake(s) if your opponent doesn't have a really good clear/sustain or needs to scale way harder than you, additionally you can call your bot lane if they are shoving and can help you

You are better off taking Rhaast if your team lacks a tank and enemy has multiple tanks, one of these is enough for you to take Rhaast

But if your team needs someone to take the backline; artillery mages/control mages/ADCs/AD casters etc you should take Shadow Assasin for sure, but he is optional because you can pick squishies with Rhaast too but you cant get out of there with Rhaast!

• Rhaast is a great bruiser

• Rhaast can rapidly heal by simply damaging enemies -good sustain-

• Rhaast won't survive if your team is sleeping

• Shadow Assasin is a great assasin

• Shadow Assasin can go in and out without any problem, thanks to his mobility with E and slow cleanse!

• Shadow Assasin is a great burster with low cd

• Shadow Assasin you CAN go in and out quickly if you LIVE to see it -squishy-

Overall, you can choose your own playstyle and even learn 2 roles on 1 champ so its great :D
He is my favorite champ.
See you all in the next guide if I even do it! Please give me feedback.