In Beast of Reincarnation, Emma’s journey through a ruined world is not a solo adventure. Standing beside her through every battle, every dangerous exploration zone, and every impossible fight is Koo — a powerful blighted canine who is much more than just a combat partner.

Koo has his own Rapport system, which tracks the growing connection between him and Emma. The more time you spend together, the stronger your bond becomes, unlocking extra abilities, new conversations, and important story moments that reveal more about their relationship.

For players chasing 100% completion, Koo’s Rapport is also tied directly to the “Closest Companion” trophy/achievement, which requires you to reach maximum Rapport with him. The good news? You don’t need to spend hours farming special materials or repeating boring tasks. Koo’s bond grows naturally as you play — as long as you remember to interact with him, care for him, and keep him involved throughout your adventure.

However, if you want to reach Koo Rapport Level 10 as quickly as possible, you’ll need to make a few simple habits part of your regular gameplay routine.

Another Beast of Reincarnation Guide: Before focusing on Koo’s Rapport, it’s worth getting comfortable with the game’s core systems. Our Beast of Reincarnation Beginner’s Guide walks through the essential mechanics, combat basics, and early progression tips to help you start Emma’s journey on the right foot.

What Does Koo Rapport Unlock in Beast of Reincarnation?

Koo’s Rapport has a maximum level of 10. Every step toward improving your bond rewards you with useful upgrades and emotional story moments between Emma and her loyal companion.

Increasing Koo’s Rapport unlocks:

• Additional skill slots for Koo’s abilities.
• More personal conversations and interactions.
• Stronger narrative moments between Emma and Koo.
• Progress toward the Closest Companion trophy/achievement.

The extra skill slots are especially valuable because Koo’s Bloom Arts play a major role during combat. As enemies become stronger and battles become more intense, having access to more abilities gives you greater flexibility and more ways to handle dangerous encounters.

Koo is not just there for story purposes — building your relationship with him directly improves his usefulness in battle.

Keep Exploring: Since much of Koo’s Rapport grows naturally while traveling, understanding how exploration works can make the process even smoother. Our Is Beast of Reincarnation Open World? Exploration Guide explains how the game’s world is structured and what you can expect while venturing beyond the Cleanse Walker.

The Best Ways to Increase Koo Rapport

1. Spend Time With Koo Inside the Cleanse Walker

The most reliable way to increase Koo’s Rapport is by interacting with him inside the Cleanse Walker, Emma’s mobile base.

Every time you return to the Cleanse Walker, don’t just rush back into the next mission. Take a moment to check on Koo and complete every available interaction. These small moments may seem simple, but they are the fastest and most consistent way to strengthen your bond.

The available interactions include:

Pet Koo

Petting Koo is one of the easiest Rapport increases you can get.

Simply approach him inside the Cleanse Walker and interact when the option appears. It only takes a few seconds, but doing this regularly slowly builds your relationship throughout the entire game.

This is one of those small actions that is easy to ignore but extremely important if you want to max Rapport without grinding later.

Give Koo a Shower

Koo can also be cleaned using the shower inside the Cleanse Walker.

This interaction is not just a cosmetic feature. Giving Koo a shower is another way to improve your connection and increase Rapport.

Taking care of Koo physically reflects the growing trust between him and Emma, making this one of the most natural ways to progress the relationship.

Talk With Koo

As you continue through the story, new conversations with Koo will become available.

These dialogue moments provide deeper insight into Emma and Koo’s bond while also contributing toward Rapport progression.

Make sure you talk with him whenever you return to the Cleanse Walker because some conversations may only appear after:

• Story progression.
• Reaching certain Rapport milestones.
• Completing other requirements.

A simple habit can make a huge difference:

Every time you return to the Cleanse Walker, interact with Koo before leaving again.

Those small increases will stack up naturally over the entire adventure.

Read Next: Building Rapport is only one part of surviving the journey. If you’re wondering whether to adjust the challenge while progressing through the story, our Beast of Reincarnation Difficulty Settings Explained breaks down every difficulty option and how each one changes the overall gameplay experience.

2. Rest at Campsites During Exploration

Another easy way to increase Koo’s Rapport is by resting at Campsites.

Unlike Cleanse Walker interactions, this method happens naturally while exploring the world. Whenever you stop to recover, manage hunger, or prepare for your next journey, Koo also receives Rapport progress.

Because Campsites are already part of normal gameplay, they become a passive way to strengthen your bond without extra effort.

A good exploration routine is:

• Explore an area.
• Rest at Campsites whenever needed.
• Continue your journey while Koo’s Rapport gradually increases.

You do not need to repeatedly rest only for Rapport farming. However, using Campsites regularly throughout the game will noticeably help by the time you reach the later stages of your adventure.

3. Feed Koo Treats to Build Your Bond

Koo also loves treats, and giving them to him is another way to increase Rapport.

To feed Koo:

1. Open your consumables inventory while exploring.
2. Select a treat.
3. Give it to Koo.

The first time you feed Koo a treat, you will also unlock the “Snack Time” trophy/achievement.

Treats are not the biggest source of Rapport progression, but they are useful when you want to push your bond closer to the next level.

Instead of ignoring treats throughout the game, save them for moments when you want a quick Rapport boost.

4. Complete Koo’s Research Projects

Koo’s research projects are another important way to increase Rapport over time.

These projects progress automatically as you gain combat experience during your adventure. You don’t need to complete any special farming tasks — simply keep playing, defeating enemies, and exploring the world.

Once a research project is completed, return to the Cleanse Walker and start the next one immediately.

To get the most out of this system:

• Always keep a research project active.
• Check the Cleanse Walker after major exploration sections.
• Start new projects as soon as previous ones are completed.

The best part about Koo’s research projects is that they work quietly in the background. While you are fighting enemies, discovering new areas, and progressing through the story, your bond with Koo continues growing without requiring extra effort.

Completionist Corner: Maxing Koo’s Rapport is only one step toward earning every achievement. For a complete checklist of every trophy, missable objective, and the most efficient route to 100% completion, check out our Beast of Reincarnation Trophy Guide & Platinum Roadmap.

Can Koo Lose Rapport in Beast of Reincarnation?

Yes, Koo’s Rapport can decrease if he falls during battle.

However, there is an important safety system in place: Koo’s Rapport will never drop below his current rank.

This means you cannot completely lose a Rapport level because Koo was defeated.

For example, if you reach Rapport Level 5 and Koo loses progress toward Level 6 after falling in combat, he will not drop all the way back to Level 4.

Because of this, there is no need to panic if Koo goes down during difficult fights. A few mistakes will not destroy your progress.

That said, keeping Koo alive is still highly recommended because:

• You avoid losing Rapport progress.
• You maintain access to his Bloom Arts.
• He remains available as a valuable combat partner.

Koo becomes more useful as your journey progresses, so protecting him during challenging battles is always worth doing.

The Fastest Way to Max Koo Rapport

If you are aiming for the Closest Companion trophy/achievement and want to reach maximum Rapport efficiently, the key is consistency.

Do not wait until the end of the game and try to grind everything at once. Instead, build these habits into your normal gameplay loop.

Whenever you return to the Cleanse Walker:

• Pet Koo.
• Give Koo a shower.
• Talk to Koo whenever dialogue is available.
• Check completed research projects.
• Start new research projects.

During exploration:

• Rest at Campsites regularly.
• Feed Koo treats whenever possible.
• Keep Koo alive during battles.

Following this routine throughout the story should naturally bring Koo close to maximum Rapport without requiring a separate grinding session.

The game rewards players who simply take care of their companion, so the best strategy is to treat Koo like a true partner rather than a mechanic you need to farm.

Koo Rapport vs Kagura Rapport: What’s the Difference?

Koo is not the only companion in Beast of Reincarnation with a Rapport system.

Kagura, Emma’s companion aboard the Cleanse Walker, also has her own relationship progression. However, the rewards you receive from each companion are completely different.

Koo Rapport Rewards

Increasing Koo’s Rapport gives you:

• More skill slots for Koo.
• Additional conversations.
• Stronger emotional moments between Emma and Koo.
• Progress toward the Closest Companion trophy/achievement.

Kagura Rapport Rewards

Kagura’s Rapport focuses more on support and survival benefits:

• Better cooking abilities.
• More meal variety.
• Improved food bonuses.

Because both systems improve through regular interaction, you should make checking on both Koo and Kagura part of your Cleanse Walker routine.

Taking a few extra seconds after returning to your base can provide major benefits later in the game.

How to Keep Koo Strong During Combat

Increasing Rapport is not just about unlocking extra dialogue or earning trophies. A stronger bond also makes Koo a more valuable partner during battles.

To get the most out of Koo:

• Use Koo’s Bloom Arts whenever enemies become vulnerable.
• Keep your Fluorescence Points stocked through successful parries.
• Avoid letting Koo fall during difficult encounters.
• Upgrade Koo’s skills whenever new slots become available.

As enemies become tougher and bosses demand better strategies, Koo’s abilities become increasingly important.

The Rapport system rewards you twice: you get deeper story moments with Emma’s companion while also making him more effective in actual combat.

Closest Companion Trophy Requirement

For players chasing full completion in Beast of Reincarnation, maxing out Koo’s Rapport is a requirement.

The trophy/achievement you need is:

Closest Companion
Reach maximum Rapport with Koo.

The best way to unlock this achievement is not by rushing at the end of the game. Start building your relationship with Koo as soon as the Rapport system becomes available.

Pet him. Talk to him. Take care of him. Complete his research projects. Keep him beside you during your adventure.

By treating Koo like a real companion instead of just another gameplay mechanic, reaching Rapport Level 10 will happen naturally — and when you finally unlock the Closest Companion trophy, it will feel like the reward for the journey you shared together.