The fastest way to complete the LEGO Batman: Legacy of the Dark Knight Buddy System challenge is to play as Robin or Nightwing, spawn a Brute in Old Gotham West’s tower combat encounter, then use their Cable Launcher to grab a regular goon while the Brute is in the arena.
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How to complete the Buddy System challenge
- Step 1: Unlock and select the right character
- Step 2: Head to Old Gotham West Brute hotspot
- Step 3: Start the combat encounter and survive to the Brute wave
- Step 4: Herd a Brute and a small goon together
- Step 5: Use the Cable Launcher on a smaller enemy
- Step 6: Repeat the attempt if the challenge does not pop
- Critical tips and mistakes to avoid
How to complete the Buddy System challenge
Step 1: Unlock and select the right character
Equip Robin or Nightwing from the character wheel once they are unlocked, as they are the only heroes with the Cable Launcher needed for Buddy System. Make sure their gadget loadout has the Cable Launcher active so the correct move triggers in combat.
Step 2: Head to Old Gotham West Brute hotspot
Travel to Old Gotham West and look for the rooftop combat encounter near the radio mast/tower in the western Old Gotham district.

This arena’s final wave is known to spawn two Brutes alongside regular enemies, making it a reliable setup for the challenge.
Step 3: Start the combat encounter and survive to the Brute wave
Activate the rooftop combat trial and clear the early waves while avoiding environmental deaths that could reset progress.

Focus on quick takedowns and crowd control until the Brutes spawn in the last wave, but avoid using heavy abilities that might accidentally kill them too early.

Step 4: Herd a Brute and a small goon together
Once a Brute spawns, kite it toward a group of smaller enemies by circle-strafing and using light attacks or dodges to reposition the crowd.

The goal is to keep at least one standard goon alive close to the Brute so the Cable Launcher can visibly connect between them in the same space.
Step 5: Use the Cable Launcher on a smaller enemy
With Robin or Nightwing selected, lock onto a regular enemy, not the Brute, and fire the Cable Launcher while the Brute is nearby.

The Buddy System challenge triggers when the game registers that the Cable Launcher’s grab is used on a smaller enemy in an arena that currently contains a Brute.

Step 6: Repeat the attempt if the challenge does not pop
If the challenge does not immediately complete, try again in the same wave: re-aim the Cable Launcher at a different goon or wait for another spawn cycle. If the Brute dies early or falls off the arena, restart the Old Gotham West combat encounter and repeat the setup until the Buddy System notification appears.

Critical tips and mistakes to avoid
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Do not use Batman-only gadgets: Batman’s Batclaw will not count; the challenge explicitly checks for Robin/Nightwing’s Cable Launcher move.
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Avoid killing the Brute too quickly: high-damage Focus abilities or explosive canisters can delete the Brute before the Cable Launcher interaction registers.
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Make sure you target a small enemy: locking onto the Brute or environmental objects will not progress Buddy System, even if a Brute is nearby.
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Watch for bugged or empty encounters: some open-world fights may spawn no Brutes; if you see only regular goons, swap to the Old Gotham West rooftop or another known Brute arena.
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Confirm challenge tracking in the Batcave: open the Batcave challenge list after your attempt to confirm Buddy System is marked as completed and to avoid repeating it unnecessarily.
Clearing Buddy System early in LEGO Batman: Legacy of the Dark Knight removes one of the more finicky Batcave challenges tied to Brute spawns, letting you focus on grind-heavy tasks like Assassin, Ninja, and Tough Guy without worrying about finding specific enemy combinations again. Getting this done in Old Gotham West while you are already tackling other combat-focused challenges is a huge time-saver for 100% completion runs.