Basic attacking an enemy champion triggers Hail of Blades on-attack, with 2 stacks remaining. While Hail of Blades is active, you gain 110% bonus attack speed and your attack speed cap is increased temporarily. Hail of Blades lasts 3 seconds but has its duration refreshed by attacking enemy champions until all stacks are consumed. This is a very hyper-aggressive rune page which will amplify Kalista's already aggressive nature and early game, allowing you to trade much more efficiently in the early game and if the enemy disrespects you may even look for an all-in for first blood.

Damaging an enemy champion heals you for 18 − 35 (based on level) (+ 20% bonus AD) (+ 10% AP). I think this is good because you can make use of this in lane a lot, especially when you can go aggressive, you will be able to tag your opponent and get free healing from this rune, pretty much nullify any minion damage you take when trading which can in turn help you have a big health advantage over your lane opponent.

Scoring a takedown on an enemy ward summons a friendly Zombie Ward in its place (10 second assist timer). Gain 1.2 bonus Attack Damage or 2 Ability Power (Adaptive) for every Zombie Ward spawned, up to 10, for a maximum of 12 bonus Attack Damage or 20 Ability Power (Adaptive). After spawning 10 Zombie Wards, gain an additional 6 bonus Attack Damage or 10 Ability Power (Adaptive). I personally think this is the better rune option out of the other 2 because as Kalista you will be playing very aggressive and having the ability to leave wards behind after killing enemy wards can be useful, preventing potential ganks when there is no need to use any trinket or control wards personally.
Heal for 1.5% (+ 2.5% per Bounty Hunter stack) of the damage dealt by your abilities, on-hit effects and items, up to 14% at 5 stacks. Benefits from Heal Power. Earn a Bounty Hunter stack for champion takedowns, up to one per unique enemy champion.Healing reduced to one third on area damage.
Converts 20% − 100% (based on level) of the healing in excess of your maximum health into a shield for an amount of up to 10 (+ 10% of maximum health).
After 6 seconds, the shield decays by 2.5% of its maximum value each second. Receiving healing, dealing or taking damage will refresh the shield duration to 6 seconds. In our build, we often build lifesteal and in particular Bloodthirster, which has a passive of giving your shields when you are lifestealing at full health, this has a great synergy with Overheal as the shield amount will be even higher, allowing you to take trades and look for potential all-ins during mid to late game. It will also prevent you from being blown up by any high burst champions.
Gain 3% (+ 1.5% per Legend stack)bonus attack speed, up to 18% with 10 stacks.
Attack speed stacks much quicker than the lifesteal rune, and you will build lifesteal from the very first item and then more lifesteal item later on so there really is not a need to go for the lifesteal rune, this will allow you to get the stacks faster and help you snowball quicker.

Kalista's Passive

Kalista's basic attack has unique properties:
Deals 90% AD physical damage.
Misses if she loses sight of her target before they hit.
Is unstoppable.
Can switch targets mid attack windup.
Makes her dash in the target direction after issuing a movement command during a windup or right after casting Pierce.
The distance scales with her Boots tier. The windup while dashing is only reduced by 0.66% per 1% bonus attack speed.

Kalista's Q

COST: 50 / 55 / 60 / 65 / 70 COOLDOWN: 8

Kalista hurls a fast and narrow spear in the target direction, dealing physical damage to the first enemy hit. If Pierce kills its target, the spear continues onward, transferring all of the dead victim's Rend stacks to the next enemy it hits. This can repeat indefinitely until the spear reaches its maximum distance.

Side Note:

This is an excellent execute ability that allows you to transfer your Rend stacks, letting you trade against your opponents giving them no chance to retaliate. This also procs your Passive, letting you hop, which means at certain times even without targets, you are able to hop over walls to either escape from a difficult spot or make an outplay. When you use this ability and Rend straight away right before it hits the target it will deal more damage than if you wait for the spear to hit the target then rend, thus a form of execute.

Kalista's W

COOLDOWN: 30 RECHARGE: 90 / 80 / 70 / 60 / 50

SOUL-MARKED: While Kalista and her Oathsworn are linked, their basic attacks and Pierce apply a Soul-Mark to their targets.
If both Soul-Marks are applied within 4 seconds, the target takes bonus magic damage (capped against non-champions), and cannot be Soul-Marked for 10 seconds. Soul-Mark deals 75 minimum damage to minions and executes them if they're below 125 health. Kalista applies the damage on-attack while the Oathsworn's damage occurs on-hit.

BONUS MAGIC DAMAGE:
14 / 15 / 16 / 17 / 18% of target's maximum health

PASSIVE: Kalista periodically stocks a Sentinel charge, up to a maximum of 2.

ACTIVE: Kalista summons a Sentinel to patrol along the area in the target direction

Side Note:

This actually gives you extremely high amount of damage when both you and your support hits the same target and proc the passive, dealing bonus magic damage. It usually takes the enemy by surprise and will help towards building an advantage in the botlane. You can also use the Sentinel to scout out certain areas, whilst it is very unreliable, you can target it to the dragon pit and this way you will know if they are doing drake or not.

Kalista's E

COST: 30 COOLDOWN: 14 / 12.5 / 11 / 9.5 / 8

Kalista's basic attacks on-hit and Pierce each lodge a spear in the target for 4 seconds, stacking up to 254 times.

Kalista rips all lodged spears from nearby enemies, dealing physical damage and slowing them for 2 seconds. The damage is increased with additional spears, but with reduced efficiency. Rend deals 50% reduced damage against epic Monster icon monsters.

PHYSICAL DAMAGE:
20 / 30 / 40 / 50 / 60 (+ 60% AD)

SLOW:
10 / 18 / 26 / 34 / 42%

Rend resets its cooldown and refunds mana if it kills at least one target.

MANA REFUND:
10 / 15 / 20 / 25 / 30

Side Note:

This will be an ability that you really have to get a feel for, as there is no exact way to determine how much damage your spear stacks will do once you activate Rend. This is your go to execute ability when you are able to stack many spears into an enemy, combining your Pierce for that high execute damage.

Kalista's Ultimate

COST: 100 COOLDOWN: 150 / 120 / 90

Kalista invokes her link, retrieving her Oathsworn and cleansing them from allcrowd control while rendering theminvulnerable, untargetable, silenced, and unable to move for 4 seconds.

Kalista's Oathsworn can dashunstoppably to a target location, and automatically does so at the end of the duration, ending Fate's Call's effects and stopping at the first enemy champion hit, knocking up all surrounding enemies and landing themselves at their basic attack range relative to the target hit.

Side Note:

An excellent engage tool and also a way to save your support from any dire situation as you are able to pull him into you. Either going back in to engage once again or simply getting out.