Here is the full list of all 40 METALLIC CHILD achievements.
Defeat the Metallic Child, Magna.
Defeat all Metallic Childs.
Defeat the Metallic Child, Icela.
Help retrieve Sly's weapons 20 times.
Defeat the Metallic Child, Spyden.
Defeat the Metallic Child, Flyer.
Defeat 20 of Catherine's modified robots.
Deal 600 damage or more to an enemy in a single hit.
Defeat the Metallic Child, Graver.
Repair Schrodinger 20 times.
Accomplish = double kills.
Defeat the Metallic Child, Faceless.
Be graded an S for battle 100 times.
Defeat the Metallic Child, Lighton.
Defeat the Metallic Child, Controd.
Install 150 Mini-cores.
Defeat the Metallic Child, Shutty.
Accomplish 30 combos.
Defeat the Metallic Child, Gigantic.
Rescue 20 survivors.
Defeat the Metallic Child, Fira.
Visit the various facilities of Life Stream.
Experience a defeat in battle.
Install 200 bugged and viral Cores.
Install 150 Super-cores.
Clear all Virtual Missions.
Clear Terminal Creed.
Defeat 3000 enemies.
Accomplish 100 triple kills.
Accomplish 30 fantastic kills.
Perform 200 Chain-skill attacks.
Go on camera 20 times, for Miamo's live stream.
Open Daviny's box 20 times.
Help deliver Trevon's virus case 20 times.
Be graded a D for battle 100 times.
Collect all Recor-Ds.
Collect all Fan-art.
Change weapons 100 times during battle.
Equip a drone 100 times during battle.
Perform 200 Take-downs.