Krul is a mighty jungle beast of a warrior who can take just as much damage as he can give. Although very weak in the early game, Krul gets incredibly strong late game if you farm right. Krul needs to farm to get strong, so try not to leave your jungle, but don't be afraid to gank and over extended laner. Krul will always come out on top in a 1v1 fight. With Krul, timing is key to secure a kill. you have to be able to time when to detonate his spectral smite. Krul's lifesteal and barrier from his dead man's rush make him seem tanker than he really is. Unfortunately, as with all good heroes, Krul has a weakness. This weakness is his mobility. Krul needs to drag out fights to win, to do so, he needs to stick to his target. With heroes that go invisible, i.e. Taka and Kestrel, you have to be able to see what you want to kill. Another one of Krul's weaknesses is sticking to his target. Slippery heroes, heroes that can kite, and heroes that can stun, (i.e. Vox, Ringo, Catherine etc.) are hard for Krul to deal with. So you have to work around that. Although Krul has a hard time getting to his target, once he gets there, there is no escape. His heroic perk give him a speed boost and a slow making escape hard. As well as that, his Ult. "From Hell's Heart" sword toss provides a stun allowing Krul to get close and cuddle.

This build is meant to lessen Krul's greatest weaknesses. Burst damage, and slippery characters. This being said, the only way to avoid burst damage is to survive the initial assault and not to get ganked. To avoid the initial assault you need to be tanky, which is what this build does. When you first look at this build, the only offensive item you see is Breaking Point, as such I can imagine your distress. Hence I feel the need to explain it. Breaking Point makes you stronger and stronger as fights drag out. Even as much as 6 or 7 stacks is devastating to an enemy. As fights drag on, this is a great edge, and since Krul thrives off long fights, this seems fitting. Shiversteel synergies well with Krul because it provides a slow, letting Krul stick to his target, and benefits the cause of tankiness. The defense items prevent damage from both WP and CP opponents. The double reflex block provided by the Crucible and the Aegis, is helpful to prevent stuns and various ultimates. The stuns will kill you. Stuns do two things, prevent you from doing anything, and prevent you from getting to your target.

I could write a page on how to play this build, but thats hard to read, so instead I will make it easy and write a list of things to always keep in mind. The number one thing to remember about this build is...
YOUR BASICS: (Listed Below, and I know, you might say "Well Duh" to some of these, but these are important)
1. You are weak early game: Always think about the mid/late game (i.e. Don't Stop Farming)
2. Studder Step: You only have +40% Attack Speed, this buffs your BASE attack speed (No Atlas Pauldron Nerf)
3. Use Your Items: All your items help you, whether it be slows, of blocks, SO USE THEM.
4. Play cautiously: Until you are at the point where you can win 85% of fights, play like an Assassin
5. Know your Enemies/Anticipate: Never underestimate your enemies and know their skills/when they use them
6. Know your Teammates: Know what your teammates are capable of and let that help you
7. Prioritize: Always know what the main objective is(Besides Win), what helps your team the most
8. PLAY AS A TEAM: You can take and give a beating, but you can't win alone. Your teammates are just as important as you are
9. Timing: Know when to emerge from the brush, when to activate you items, and when to use your abilities

Why did I choose these items?
Boots: Movement speed is crucial to Krul. You need to be able to get to your target quickly.
Breaking Point: This grants Weapon Power and Crit. Chance the longer you are in combat. This is where all of your damage comes from. The attack speed is nice as well because it gets you your Smite Stacks faster.
Shiversteel: This allows you to slow down your target to your speed, meaning you can stick, and when you stick, your breaking point stacks and allows you to accomplish your goal of dragging out a fight.
Crucuble: The extra health lets you survive longer in fights, even after a bursty initial assault. The reflex block for you and your team shuts down AOE Ultimates, Single Target Ultimates Stuns and effects from Atlas Paulderon.
Altas Paulderon: This slows opponents attack speed down, meaning that they effectively deal less damage. The extra Shield and Armor is just an added bonus.
Aegis: The shield is great for lessening damage from CP heroes. The second reflex block is great for many purposes listed above.