Discover the best solo class in Borderlands 4. Complete guide to Vex the Siren’s abilities, builds, and essential tips for dominating Kairos as a single player.
Choosing Your Solo Vault Hunter in Borderlands 4
Starting your solo journey through planet Kairos? You’re facing one of the most important decisions in Borderlands 4 – picking the right Vault Hunter for single-player mayhem. With four distinct classes to choose from (Siren, Forgeknight, Gravitar, and Exo-Soldier), the choice can feel overwhelming, especially when you know you’ll be tackling everything alone.
After extensive testing across all difficulty levels and countless hours of solo gameplay, there’s one clear winner that stands above the rest for single-player adventures. Let me break down why Vex the Siren is your best bet for conquering Borderlands 4 solo, plus give you the insider tips you need to dominate from day one.
Why Vex the Siren Dominates Solo Play
The Short Answer: Vex is a one-woman army wrapped in mystical powers and elemental chaos.

The Real Answer: She’s the only Vault Hunter designed from the ground up to handle multiple threats simultaneously while maintaining incredible survivability. Think of her as a magical Swiss Army knife – she’s got a tool for every situation, and most of those tools involve summoning otherworldly creatures to do her bidding.
What Makes Vex Special for Solo Players
Unlike other Vault Hunters who might excel in team scenarios, Vex thrives when she’s flying solo. Her entire kit revolves around creating her own backup through summons, maintaining health through life-stealing abilities, and adapting to any enemy type through elemental attunement.
The beauty of playing Vex solo is that you’re never truly alone. Between her Phase Familiar companion and her Death Ringer clones, you’ll always have allies watching your back – even if they’re supernatural manifestations of your own power.

Vex’s Three Game-Changing Abilities Explained
Phase Familiar: Your Permanent Battle Buddy
This isn’t just another pet – Trouble (yes, that’s its name) is your constant companion that evolves based on your weapon choices. Here’s what makes this ability incredible for solo play:
Key Benefits:
- Provides consistent DPS while you focus on positioning
- Adapts to your weapon’s element automatically
- Acts as a distraction for enemies, giving you breathing room
- Becomes significantly more powerful when actively triggered

Elemental Attunement System:
- Blue (Shock): Effective against shields and synthetic enemies
- Purple (Kinetic): Grants you life-stealing capabilities
- Red (Fire): Burns organic enemies over time
- Green (Caustic): Melts armor and deals persistent damage
- Yellow (Radiation): Spreads damage between nearby enemies
The genius of this system is that you’re essentially getting two characters worth of elemental coverage – your weapon and your familiar working in perfect harmony.
Incarnate: Becoming the Avatar of Destruction
When things get serious, Vex literally transforms into a supernatural force. Incarnate is your “oh crap” button that instantly maxes your health and turns you into a magical artillery platform.
Why It’s Perfect for Solo Play:
- Instant full heal saves you from certain death situations
- Eldritch Blast lets you clear rooms of enemies effortlessly
- Increased movement speed helps with positioning and escaping danger
- Overshield potential through skill tree upgrades adds extra survivability
This ability essentially gives you a temporary god mode that can turn any desperate situation into a victory. It’s particularly effective against bosses where you need sustained damage output.

Death Ringer: Your Personal Army
Death Ringer summons two clones of Vex – either scythe-wielding Reapers or rifle-carrying Specters. This is arguably the most versatile ability for solo players because it effectively triples your damage output.
Strategic Advantages:
- Reapers excel at close-range crowd control
- Specters provide ranged support and precision damage
- Fast cooldown means you can maintain almost constant clone support
- Regeneration bonuses when clones die keep you healthy
The ability to have two AI-controlled versions of yourself fighting alongside you makes even the toughest encounters manageable. Plus, watching three Vexes tear through enemies never gets old.
Early Game Strategy: Surviving the Learning Curve
Here’s the reality check – Vex starts out relatively fragile compared to tankier classes like the Forgeknight. But don’t let that discourage you. Her power curve is more like a rocket ship than a gentle slope.
Levels 1-10: Building Your Foundation
Start with Phase Familiar immediately. While Death Ringer might look flashy, Trouble provides consistent support that makes the early grind much more manageable. Focus on:
- Weapon variety: Experiment with different elemental weapons to understand attunement
- Positioning: Learn to let Trouble tank while you deal damage from range
- Passive skills: Prioritize survivability over damage initially
Levels 10-20: The Power Spike
This is where Vex transforms from struggling newcomer to supernatural powerhouse. Energy Vampire and Coven become available, dramatically improving your sustain. Switch to Death Ringer for boss fights while keeping Phase Familiar for general exploration.
Late Game: Unleashing Hell
Once you hit the higher levels, Incarnate becomes your primary tool for melting everything in sight. The combination of all three abilities creates a playstyle that’s both incredibly powerful and surprisingly strategic.

Essential Loadout Tips for Solo Success
Weapon Selection Strategy
Primary Weapon: Always carry a kinetic damage weapon for life-leech sustain Secondary: Choose based on the area’s primary enemy type Heavy Weapon: Keep an explosive option for crowd control Ordnance: Throwing knives are perfect for critical hits and “Second Chance” moments
Skill Tree Priorities
Early Game Focus:
- Energy Vampire – Sustain through ability usage
- Coven – Additional survivability bonuses
- Phase Familiar improvements – Extend Trouble’s effectiveness
Mid Game Development:
- Death Ringer enhancements – Longer clone duration and damage bonuses
- Elemental amplification – Boost your attunement effects
- Movement skills – Improved positioning and escape options
End Game Mastery:
- Incarnate upgrades – Maximum carnage mode
- Overshield generation – Ultimate tankiness
- Elemental mastery – Become a walking natural disaster
Combat Tactics That Actually Work
Crowd Control Mastery
Vex excels at controlling the battlefield through strategic ability usage:
- Open with Phase Familiar to establish map control
- Position carefully – let your summons engage first
- Use Death Ringer when overwhelmed
- Save Incarnate for emergency healing or boss burn phases
Boss Fight Strategy
Solo boss fights require a different approach than general combat:
- Phase one: Use Death Ringer for sustained DPS
- Emergency phases: Incarnate for healing and damage
- Weapon swapping: Match elements to boss weaknesses
- Positioning: Abuse Vex’s mobility to avoid major attacks
Why Other Classes Fall Short for Solo Play
Forgeknight Limitations
While incredibly tanky, the Forgeknight lacks the versatility needed for varied solo encounters. Great for team play, but can struggle with certain enemy types when alone.
Gravitar Challenges
Powerful but requires specific positioning and setup that’s harder to achieve consistently in solo scenarios.
Exo-Soldier Issues
Excellent damage output but limited survival options when you’re the only target on the battlefield.
Advanced Solo Techniques
Elemental Rotation Mastery
Learn to switch weapons based on enemy spawns, not just individual targets. Approaching a mixed group? Start with caustic to soften armor, switch to shock for shields, finish with kinetic for sustain.
Ability Cycling
Master the art of chaining abilities for maximum uptime. Use Phase Familiar’s passive benefits to set up Death Ringer positioning, then transition into Incarnate for the finishing blow.
Resource Management
Unlike team play where you can rely on others for revives, solo play demands careful attention to health, shields, and ammunition. Vex’s life-leech capabilities make her uniquely suited to sustained solo combat.
Platform Performance Considerations
Whether you’re playing on PC through Steam, PlayStation, or accessing through the official Borderlands portal, Vex’s abilities perform consistently across all platforms. Her summon-heavy playstyle doesn’t rely on precise aiming mechanics that might vary between controller and mouse/keyboard setups.
Building Your Solo Empire
Once you’ve mastered Vex’s basics, the real fun begins. Consider exploring advanced builds and optimization strategies:
- Specialization mastery: Learn about advanced specialization skills to enhance your chosen playstyle
- Character progression: Understand the complete character breakdown for all four Vault Hunters
- End-game preparation: Plan your transition into post-campaign activities
The Bottom Line on Solo Borderlands 4
Vex the Siren isn’t just the best solo class in Borderlands 4 – she’s designed to make solo play feel like you’re commanding a small army. Her combination of survivability, versatility, and sheer destructive potential makes her the perfect choice for players who want to experience everything Kairos has to offer without relying on teammates.
The learning curve might be steeper than picking a straightforward tank or soldier class, but the payoff is enormous. Once you master her elemental attunement system and ability synergies, you’ll wonder how you ever played Borderlands any other way.
Ready to embrace your inner supernatural badass? Vex is waiting, and planet Kairos won’t know what hit it.
Quick Start Checklist:
- Choose Phase Familiar as your starting ability
- Experiment with different elemental weapons early
- Focus on Energy Vampire and Coven skills first
- Switch to Death Ringer around level 10
- Save Incarnate for emergencies until you have supporting skills
- Always carry throwing knives as your ordnance weapon
Pro Tip: Don’t sleep on weapon experimentation. Vex’s power comes from adapting to situations, and the more comfortable you are with different weapon types and elements, the more unstoppable you’ll become.
Now get out there and show Kairos what a solo Siren can do.