The Voidwalker is the sub-class for the Warlock, and is a sub-class designed to deal as much damage as possible. As a Voidwalker Warlock you'll be able to utilise Nova Bomb in order to throw a massive projectile for huge damage. What's particularly interesting about this Super is that it can be changed in two ways, with one upgrade path allowing it to detonate into multiple projectiles or the second, providing the player with manual control over its detonation. 

As you'll note below, the Voidwalker Warlock can improve their Grenades which provide utility (Vortex and Axion), or damage (Scatter). In addition, and as is standard with all Warlock sub-classes, their sub-class ability is known as Rift and allows them to improve themselves and their team. Finally and unlike other classes, the Warlock (and Voidwalker) gains access to Glide, allowing you to Blink. 

Super

• Nova Bomb: Hurl an explosive bolt of Void Light at the enemy, disintegrating those caught within its blast.

Grenades

• Axion Bolt: A bolt of Void Light that forks into smaller bolts on impact that seek out enemies.
• Vortex Grenade: A Grenade that creates a Vortex which continually damages enemies trapped inside.
• Scatter Grenade: A grenade that splits into many submunitions and covers a large area with multiple explosions.

Rift

• Healing Rift: Press and hold Circle/B to conjure a Well of Light that continuously heals those inside it.
• Empowering Rift: Press and hold Circle/B to conjure a Well of Light that increases weapon damage for those inside it.

Jump

• Blink: Jump while airborne to teleport a short distance.
• Burst Glide: Jump while airborne to activate Glide and start an airborne drift with a strong initial boost of speed.
• Strafe Glide: Jump when airborne to activate Glide and start an airborne drift with strong directional control.

Passive Tree - Attunement of Chaos

• Bloom: Void ability kills cause enemies to explode.
• Cataclysm: Nova Bomb travels slowly and seeks enemies. Detonations shatter into smaller seeker projectiles. Fire your weapon at the Nova Bomb to detonate it early.
• Chaos Accelerant: Hold L1 to draw power from your Super to overcharge your grenade, making it deadlier and more effective.
• Entropic Pull: Strike an enemy with this Melee Ability to drain your enemy’s life force and use it to recharge your grenade.

Passive Tree - Attunement of Hunger

• Devour: Kill an enemy with this melee ability to fully regenerate your health. For a short time afterward, kills restore additional health.
• Feed the Void: Hold L1 to consume your grenade energy to regenerate your health. Grants the Devour effect.
• Insatiable: While the Devour effect is active, killing enemies extends its duration and recharges your grenade.
• Vortex: Nova Bomb creates a singularity which continually damages enemies trapped inside.