Hello guys, welcome to my first guide. I hope you will try it out and see how good it works :)
So my build is basically just about getting the combination of Lethal Tempo, Kraken Slayer and Blade of the Ruined King. The keystone will let you experience a huge power spike after BORK, that isn't even fair anymore. The earlier you get your two items, the more impactful the power spike will be. I usually aim to get BORK around 16-20 minutes into the game. From this point you will deal tons of damage and it will only become better for you the further the match goes.

So, let's take a look at the three components.

(1) Lethal Tempo

After 1.5 seconds upon damaging an enemy champion you gain 40% − 110% (based on level) bonus attack speed and your attack speed cap is increased for 3 seconds. Attacking a champion while the effect is active extends the duration to 6 seconds.

(2) Kraken Slayer

Stats
+65 attack damage
+25% attack speed
+20% critical strike chance

UNIQUE – BRING IT DOWN: Basic attacks on-attack grant a stack for 3 seconds, up to 2 stacks. At 2 stacks, the next basic attack consumes all stacks on-attack to deal 60 (+ 45% bonus AD) bonus true damage on-hit.
MYTHIC PASSIVE: Empowers each of your other Legendary items with 10% bonus attack speed.

(3) Blade of the Ruined King

Stats
+40 attack damage
+25% attack speed
+10% life steal

UNIQUE – MIST'S EDGE: Basic attacks deal (Melee role: 10% / Ranged role: 6%) of the target's current health bonus physical damage on-hit, with a minimum of 15 against all units and a maximum of 60 against minions and monsters.
UNIQUE – SIPHON: Basic attacks on-hit against enemy champions apply a stack for 6 seconds, stacking up to 3 times. The third stack consumes all stacks to deal 40 − 150 (based on level) bonus magic damage on-hit and slow the target by 25% for 2 seconds, while also granting you 25% bonus movement speed for the same duration (20 second cooldown).


Ok, to summarize what you get here...
You get 105 AD, 60% AS, 20% Crit and 10% Lifesteal, in addition you get 60(+45% AD) bonus TRUE DAMAGE ON HIT plus current health bonus physical damage on hit. And now in addition to all of this your Lethal Tempo will increase your attack speed for another 80% at the time you reach the two item spike.
Kraken Slayer + Blade of the Ruined King together already deal a juicy amount of damage, but Lethal Tempo brings it on another level. When you time it correctly you jump on the enemy with Q Dance of Arrows as soon as Lethal Tempo is activated. The bonus attack speed from Dance of Arrows + Lethal Tempo will make lamb shoot her bow real quick and all the on-hit damage shreds every opponent in seconds.
Also I recommend only to only buy one more attack speed item after Blade of the Ruined King. You get attack speed per level from Lethal Tempo, attack speed per 3 stacks from Dance of Arrows and attack speed per legendary item from Kraken Slayer. You are guaranteed to have a lot of attack speed later on so there is no need to focus on getting more attack speed. You can still combine items like Runaan's Hurricane and Wit's End but it's very situational. If you prefer Phantom Dancer over Runaan's Hurricane you can also take it as the standard 3rd item. You don't really need the extra attack speed that Runaan's Hurricane has but I prefer the bullet spread passive from this item so I don't run Phantom Dancer even though it's an amazing item for Kindred aswell.

Most of the time Kindred player in high elo prefer Galeforce over Kraken Slayer. The Galeforce active provides another dash for Kindred that can help you to dodge enemy skillshots.
Also the movement speed bonus from the mythic passive is nice to have and in fast high elo games, the Galeforce into The Collector combo spikes even better.
Nevertheless, Kraken Slayer does more damage and it gives you much more attack speed from the mythic passive.
The on-hit synergy from Kraken Slayer and Blade of the Ruined King makes you deal crazy damage and it's a solid foundation for every possible build.
What you will build changes from game to game but i want to talk about the third item choice aswell.

After you build Kraken Slayer into Blade of the Ruined King you have a solid foundation for many different builds. I nearly always go for a Runaan's Hurricane as a third item, followed by an Infinity Edge. If you are against a team that builds not much armor then this will be a solid build. It gives you extreme amounts of damage but less utility. Against AP heavy teams you could go for a Wit's End as a 3rd or 4th item. When you face champions like Mordekaiser or Darius, make sure to get Mortal Reminder and Lord Dominik's Regards as your 4th and 5th item (you can skip Infinity Edge vs them, the antiheal and armor penetration stats are way more important in this case).

Many people think that Hail of Blades is a better Lethal Tempo but that's not true at all. They are very different keystones and it's not like one of them is overall better than the other. So far it seems like Hail of Blades is really good on Kindred if you play them in a lane, but in the Jungle it's truly not so good. You can proc your E Mounting Dread really quick with Hail of Blades and it can be strong with Ability Haste/ Lethality builds but overall it doesn't feel as good as any keystone of the Precision Tree.

Sure, you can just build these items and play it with Press the Attack or Conqueror, then you get a normal meta build for Kindred. At the end of the day you need to find out what works best for your personal playstyle!

I recommend doing a 3-camp-clear into gank or invade. Then watch out for scuttle + another gank/invade. Don't mind dying if ur team gets multiple early kills out of it (in messy scuttler fights for example). If you survive your early action then clear the rest of the camps + gank again or do a second full clear. Aim to go first back with 1300+ gold. Kindred is strong early and can wait with first back until 2k gold (+) if there are many opportunities to do stuff early then use it.
Prefer ganking over farming since you want to pressure the enemy, help your team and get a lead. Still make sure that your jungle clear is efficient and complete. If you die ganking botlane while your topside jungle is full and Rift Herald is up the enemy jungle can take it all. Such stupid mistakes can easily lose you the game.
Always keep an eye on the lanes that are gankable and plan your ganks in advance.
The more experienced you are the more you will see things happen before they actually happen, especially as Kindred this is helpful to do.

To get the maximum out of your keystone rune Lethal Tempo you should always keep an eye on it. Try to activate it with your W Wolf's Frenzy, then close the gap to them with your Q Dance of Arrows or Flash and attack them. Your arrows will come so quick and hit so hard, their HP bars will just melt down.
This build makes Kindred extremely dangerous to tanks but also squishy carries and assassins will have a hard time to deal with you.
Never forget that you are still a squishy adc with no support and short range. Always play accordingly to the given situation and try to keep low death. If YOU play it correctly you will nearly never end up with three loosing lanes and most likely be quite fed.
That's exactly what you want as Kindred, if they snowball early they become an unstoppable 1v9 carry.

Good luck trying this build :)

Even though Lethal Tempo is not a common keystone rune for Kindred, this build deals crazy damage and I think you can easily use it in Ranked Solo/Duo matches. It is significantly weaker than Press the Attack early on but as I mentioned, after 2 items you will notice how Lethal Tempo starts to shine. For my part, I was really surprised about the damage from this build when I tried it the first time. Also it becomes even stronger when the game keeps going.
I don't play in D2+ so I don't recommend the build for high elo. Galeforce into The Collector with Press the Attack is probably superior. The lower elo you are the more efficient the Lethal Tempo build will be, it just enhances your ability to actually 1v9 games in any situation. Don't forget that Kindreds passive Mark of the Kindred marks make this build even more ridiculous, try to get the 4 marks early (until 20 min) and get to at least 7 marks when the game is on 25-30 min. You will be scary as hell :)