Code Vein II Blood Code Guide

Blood Codes are the foundation of your entire build in Code Vein II. Think of them as dynamic classes that you can swap on the fly, each one transforming your stats, attributes, and playstyle to match specific NPC partners. Unlike traditional RPGs where you're locked into a class choice, Blood Codes let you experiment freely and adapt to any situation. Here's everything you need to know about unlocking, leveling, and optimizing these powerful tools.

What Do Blood Codes Do?

Blood Codes fundamentally reshape how your character functions. When you equip Lou's Blood Code, you're not just getting a stat boost—you're transforming into a defensive specialist with reduced stamina costs for guarding. Switch to Josee's Blood Code, and suddenly you're gaining Ichor from attacks but taking damage when your Ichor is full. Each Blood Code represents a specific NPC's fighting style, complete with their strengths and weaknesses.

The key here is understanding that Blood Codes control three critical elements: your base attributes (Strength, Dexterity, Mind, Willpower, Vitality, Fortitude), your derived stats (HP, LP, Stamina, Ichor), and unique traits that activate under specific conditions. This creates a layered system where your equipment, attributes, and traits all interact to define your effectiveness in combat.

Blood Code stat differences

The Attribute Burden System

Here's where things get interesting. Every weapon, jail (the new term for veils), and defensive forma you equip applies burden to specific attributes. You'll want your burden values to stay at or below your attribute scores, or you'll enter the "Overburdened" state.

Being Overburdened isn't necessarily bad—it's a calculated risk. You gain benefits alongside penalties, creating opportunities for skilled players to exploit powerful equipment combinations. For example, if your Vitality burden exceeds your Vitality attribute, you'll suffer reduced mobility when your LP drops below a threshold. However, you might gain access to stronger equipment that wouldn't normally be available at your attribute level.

Burden Effects on Dodging:

The dodge system directly impacts your survival. Quick stepping gives you superior invincibility frames and positioning options, while fat rolling leaves you vulnerable. Most players should aim for normal load as their baseline, only accepting heavy load when the equipment benefits clearly outweigh the mobility loss.

Dodge performance by burden

Blood Code Traits and Activation Requirements

Every Blood Code comes with three unique traits that activate under specific conditions. What most players miss is that these conditions are almost always tied to your burden state. You'll see requirements like "No Overburden Effect," "Any Overburden Effect," or specific margin requirements.

Let's break down margin requirements since they're the trickiest. Lou's Blood Code at E-rank has a trait requiring "Mind Margin 14." This means after all burden is applied, you need 14 points of Mind remaining. Since E-rank Lou gives you exactly 14 Mind, you need zero Mind burden to activate this trait. However, when you upgrade to A-rank Lou with 26 Mind, you can now accept up to 12 points of Mind burden and still keep the trait active.

Common Trait Activation Types:

• No Condition: Always active when Blood Code is equipped
• No Overburden Effect: Requires all attributes below burden threshold
• Any Overburden Effect: Activates only when at least one attribute is Overburdened
• Margin Requirements: Specific attribute must have X points remaining after burden

Pro tip: Check your traits menu regularly in the stats screen. Active traits display in white text, while inactive ones are grayed out. This instant feedback helps you optimize your loadout without guessing.

Trait activation status display

Unlocking New Blood Codes Through Partner Bonds

You'll acquire new Blood Codes by forming bonds with NPCs throughout your journey. Most Blood Codes unlock automatically as you progress through main story quests and meet new characters. However, there's a catch—you might need to actually take an NPC as your active partner before receiving their Blood Code.

For instance, Iris's Blood Code won't appear until you bring her along on missions. The game doesn't explicitly tell you this, so if you're missing a Blood Code from an NPC you've met, try partnering with them for a few encounters. After some combat together, rest at a Mistle and they should offer their Blood Code.

Each NPC represents a distinct playstyle archetype. The pink-haired hammer wielder focuses on Strength and Balance with high HP but lower Dexterity and Ichor. The greatsword berserker vampire boosts Strength and Ichor recovery but drains health when Ichor is full. The mysterious robed figure enhances Willpower and Ichor while increasing debuff application rates. Your early game strategy should involve collecting as many Blood Codes as possible to understand which playstyles resonate with your preferred approach.

Leveling Blood Codes: The Proficiency System

Blood Code progression uses a proficiency system that functions independently from your Haze earnings. You'll gain proficiency by defeating enemies while a specific Blood Code is equipped, but here's the thing—proficiency gain scales with area difficulty, not enemy Haze rewards.

Early areas like the Sunken City will quickly stop providing proficiency for anything above D-rank Blood Codes. Meanwhile, the Undead Forest continues rewarding proficiency all the way to B-rank. This means you need to consciously move to higher difficulty zones if you want to rank up your Blood Codes efficiently.

Blood Code Ranking Progression:

Not all Blood Codes follow the standard E-D-C-B-A progression. Lou's Blood Code skips B-rank entirely, jumping from C-rank to A-rank. Josee starts at E-rank but leaps to C-rank for her first upgrade. Valentin begins at D-rank and promotes directly to B-rank. There's no universal pattern, so don't assume you know what's coming next.

Once you max out proficiency, claiming your upgraded Blood Code depends on whether the NPC is your active partner. If they're with you, simply rest at any Mistle and they'll initiate dialogue to grant the upgrade. If they're not your partner, find them in the world and select the "Catch up" conversation option. If neither method works, the upgrade is probably story-gated.

Boosters

Boosters function as passive equipment that enhance your capabilities beyond what Blood Codes provide. You'll find boosters that increase specific attributes, activate effects with certain weapon types, or provide conditional benefits during combat. The variety is extensive, allowing you to fine-tune your build for specific encounters or playstyles.

What makes boosters particularly valuable is their trait system. Some boosters have traits with no activation requirements, making them perfect for reaching the attribute thresholds needed to activate more demanding Blood Code traits. Others have powerful effects locked behind steep requirements, but clever use of Blood Code swapping can make these accessible.

Consider boosters as the glue that holds your build together. Your Blood Code provides the foundation, your equipment determines your burden state, and boosters fill the gaps to activate the specific traits and bonuses you need for your strategy.

Early Game Blood Code Optimization

Your starting Blood Codes will likely be Lou and Josee, both beginning at E-rank. Lou focuses on defensive play with guard stamina reduction and Mind attribute emphasis. Josee leans aggressive with Ichor gain on hit but health drain when Ichor caps. For more details on the latest updates and features, check out our Code Vein II Exclusive Preview.

In the early game, prioritize keeping your burden under control rather than chasing the highest damage weapons. A quick step dodge will save your life more often than a few extra points of attack power. Equip lighter weapons and jails initially, then gradually introduce heavier equipment as you rank up your Blood Codes and gain more attribute points.

Focus on maxing proficiency for your preferred Blood Code first. The stat increases from ranking up provide more immediate benefit than spreading your efforts across multiple Blood Codes. Once you hit C-rank or B-rank with your main Blood Code, you'll have enough attribute headroom to experiment with heavier equipment without sacrificing dodge performance.

Advanced Blood Code Strategies

Once you've collected multiple Blood Codes at various ranks, you can start building specialized loadouts for specific situations. Keep lower-ranked Blood Codes equipped for when you want to deactivate certain traits, sometimes a trait's penalty outweighs its benefit, and using a lower-rank version makes it easier to break the activation requirement.

Blood Code swapping mid-mission is viable but risky. Your HP, Stamina, and Ichor values change when you swap, potentially leaving you vulnerable if you switch at the wrong moment. Always swap near a Mistle or during a safe moment, never mid-combat unless you're absolutely certain about the stat changes.

Pay attention to how different Blood Codes interact with your weapon choices. Some Blood Codes heavily favor Strength scaling, making them perfect for greatswords and hammers. Others boost Dexterity and Mind, synergizing better with fast weapons and heavy forma usage. Match your Blood Code to your preferred weapon class for maximum efficiency. Learn more about upcoming releases in Biggest Game Releases For January 2026.

Trait Synergy and Link Traits

Beyond Blood Code and Booster traits, you'll unlock Link Traits by partnering with specific NPCs. These traits activate when that character accompanies you, adding another layer to your build optimization. Link Traits often complement the partner's Blood Code, creating natural synergies when you use their Blood Code while they're your active partner.

The real power comes from stacking multiple trait sources. Your Blood Code provides three traits, your Boosters add more, and your Link Trait from your partner creates a final bonus. When you carefully control burden to activate specific traits while keeping others inactive, you can create incredibly specialized builds that excel in narrow situations.

Trait Stacking Priority:

1. Identify your core strategy (aggressive, defensive, forma-heavy)
2. Select a Blood Code with traits supporting that strategy
3. Add Boosters that either activate more traits or enhance existing ones
4. Choose a partner whose Link Trait complements your approach
5. Adjust equipment burden to activate maximum beneficial traits

Common Blood Code Mistakes to Avoid

Many players fall into the trap of treating Blood Codes like permanent class choices. You should be swapping regularly based on the content you're tackling. Exploring a new area? Use a defensive Blood Code with high HP and stamina. Facing a boss weak to magic? Switch to a Mind and Willpower focused Blood Code for maximum forma damage.

Another mistake is ignoring the proficiency system entirely. You'll naturally gain some proficiency through normal play, but actively grinding in appropriate zones makes a massive difference. Spending 30 minutes in the right area can push a Blood Code up an entire rank, providing stat increases equivalent to several character levels.

Finally, don't neglect lower-ranked Blood Codes once you've unlocked higher ranks. Keep a variety of ranks available for different burden configurations. Sometimes you'll want the lower stats of an E-rank Blood Code to make specific trait deactivation easier, or to reduce burden when testing new equipment combinations.

The Blood Code system in Code Vein II offers incredible depth for players willing to engage with its mechanics. Start simple, experiment often, and gradually build your understanding of how attributes, burden, and traits interact. Before long, you'll be creating specialized builds that feel completely unique to your playstyle. For more insights into partner mechanics, read our Code Vein II Partner Deep Dive.