In Hero Siege Season 9, the Samurai Explosive Kunai (EK) build has become one of the most efficient setups for both early progression and endgame farming. It stands out because it clears entire screens in seconds while still offering enough mobility to stay safe in high-pressure content.

The build’s popularity mainly comes from how it interacts with scaling mechanics. Explosive Kunai scales with Magic or Arcane Skill Damage, but its throw rate is tied directly to Attack Speed. This creates a unique hybrid style where fast melee-speed weapons enable rapid projectile spam, while magic scaling turns each explosion into a massive area wipe. Once fully set up, this combination allows players to melt dense packs in Hell difficulty maps, including Hell 4 and Hell 5, without slowing down.

Core Skill Setup and Specialization

The foundation of the build revolves around a few key skills that define both its damage and mobility.

Explosive Kunai is your primary damage skill. Every thrown kunai detonates on contact with enemies or terrain, and when multiple projectiles overlap, the explosions stack to create large cascading bursts. This is what gives the build its famous screen-clearing power.

Smoke Bomb plays a critical supporting role. It applies a strong debuff that increases enemy damage taken significantly, often making bosses and elites much easier to burst down. Proper use of Smoke Bomb before engaging tougher enemies is essential for maintaining consistent kill speed.

Quick Slash is not used for damage but for movement. It allows you to reposition instantly, skip dangerous ground effects, and maintain momentum while farming maps. In practice, it turns the Samurai into a highly mobile farming machine.

For passives, most players prioritize Warrior Spirit and Live by the Sword to stabilize core stats. After that, points are usually invested into Evasion or flat Magic Skill Damage nodes depending on gear progression and survivability needs.

Specialization Tree Choices

The Explosive Kunai specialization tree offers two main progression paths, and both are viable depending on playstyle.

The Chainsplosion path is generally considered the stronger option for mapping. It improves how explosions chain across packs and increases targeting efficiency, making it ideal for dense map layouts where speed matters more than precision.

The Double Blast and Split Up path focuses more on raw coverage. It allows kunais to explode multiple times and split into additional projectiles, dramatically increasing screen coverage. This path feels slightly more chaotic but excels when you want maximum AoE density.

Most endgame players tend to favor Chainsplosion once additional projectile scaling is available through Hero Tree upgrades, since it provides smoother clears and more consistent chaining across large enemy packs.

Gear and Weapon Rules

Gear selection is where many new players make mistakes with this build. One of the most important rules is that Explosive Kunai cannot be cast while holding throwing weapons or battle darts. Instead, you must use a melee weapon, typically a sword, to enable casting.

During leveling, the best approach is to find the fastest possible melee weapon. Attack speed is extremely valuable early because it directly increases your casting rate. Socketing Amethysts into your weapon is also a strong early boost since it provides flat scaling that helps the skill snowball.

Stat priorities should focus on a few key modifiers. Arcane Skill Damage and Magic Skill Damage are your primary damage multipliers, while Attack Speed ensures smooth projectile spam. As you progress into endgame, global damage multipliers from Hero Tree perks such as Magic Duality, Wizard Wrath, and Time Surge become extremely important for scaling into high Hell tiers.

Pros and Cons Overview

The Explosive Kunai Samurai has a very clear identity as a fast farming and mapping build, but it does come with trade-offs.

Pros include extremely fast map clearing once the build comes online, often around level 40 or so. The screen-wide explosions allow you to delete packs instantly while maintaining high mobility. The built-in movement from Quick Slash also makes it one of the safer ranged playstyles, since you are rarely forced to stand still. It naturally bypasses many map obstacles due to its mobility tools.

On the downside, the build is not as strong in pure single-target situations. Boss fights tend to take longer compared to its mapping speed, which can feel inconsistent in endgame encounters. It is also relatively performance heavy, since large chain explosions can reduce FPS on lower-end systems. Finally, the build requires active aiming—missing throws can reduce DPS uptime and slow down clear speed.

Overall, the Explosive Kunai Samurai remains one of the most efficient and satisfying builds in Hero Siege Season 9. It combines speed, safety, and explosive clear potential in a way that few other builds can match, making it a top choice for both new league starters and experienced endgame farmers.