Quick Answer
The Flood is Halo CE's terrifying third faction — a parasitic organism that infects and mutates hosts. They appear in Mission 6 (343 Guilty Spark) and fundamentally change the game's combat from tactical cover-based fighting to aggressive crowd control. Three forms exist: Infection Forms (small, swarming, infectious), Combat Forms (infected hosts wielding weapons), and Carrier Forms (walking bombs that release Infection Forms). The Shotgun is the definitive Flood-killing weapon.
The Flood section contains spoilers for one of gaming's greatest surprises. If you haven't played Halo CE before, you may want to experience the Flood reveal firsthand before reading this guide.
Flood Forms
Infection Forms
Small, popcorn-sized creatures that swarm in large numbers. Individually harmless but deadly when they reach you — they burrow into your armor and damage health directly.
| Stat | Detail |
|---|---|
| Size | Very small (popcorn-sized) |
| Health | One shot from any weapon |
| Attack | Burrows into armor, damages health |
| Threat Level | Low (individually), Medium-High (swarms) |
| Best Weapon | Assault Rifle (volume of fire), melee |
Strategy: AR spray eliminates swarms efficiently. Melee works in a pinch. Never let them reach you — they bypass shields entirely.
Combat Forms
The primary Flood threat. These are infected human, Elite, or other hosts animated by the Flood parasite. They shamble, rush, and attack with whatever weapons their host carried.
| Stat | Detail |
|---|---|
| Size | Human/Elite-sized |
| Health | Medium (one Shotgun blast kills) |
| Weapons | Whatever the host carried (AR, Magnum, Plasma Rifle, Shotgun) |
| Threat Level | High |
| Best Weapon | Shotgun — one blast to center mass |
| Special | Can be resurrected by Infection Forms |
Strategy:
- Shotgun is the answer: One blast to center mass destroys any combat form
- Never stop moving: Combat forms rush aggressively. Retreat while firing.
- Destroy the body: Combat forms can be reanimated by Infection Forms. Shoot corpses to prevent resurrection.
- Watch for armed forms: Combat forms with Shotguns or Rocket Launchers are extremely dangerous
Carrier Forms
Bloated, waddling Flood forms filled with explosive gas and Infection Forms. When killed or when they reach you, they explode — releasing a cloud of Infection Forms.
| Stat | Detail |
|---|---|
| Size | Large, bloated |
| Health | Low-Medium |
| Attack | Self-destructs, releases Infection Forms |
| Threat Level | Medium (solo), High (groups in confined spaces) |
| Best Weapon | Magnum (accurate, ranged), any ranged weapon |
Strategy:
- Shoot from distance: Detonate them before they get close
- Never melee them: The explosion damage is significant
- Clear the Infection Forms: After a Carrier detonates, immediately switch to AR or melee to clear spawned Infection Forms
- Chain reactions: Carriers near other Carriers create chain explosions — extremely dangerous in confined spaces
Flood Combat Philosophy
The Flood require a fundamentally different approach than fighting the Covenant:
| Aspect | Covenant Combat | Flood Combat |
|---|---|---|
| Pace | Tactical, cover-based | Aggressive, constant retreat |
| Priority | Elite shields → headshot | Crowd control, body destruction |
| Positioning | Hold angles, use cover | Never stop moving backwards |
| Weapon Preference | Precision weapons (Magnum) | Close-range spread (Shotgun) |
| Grenades | Initiate and flush out | Situational (Carrier clusters) |
Mission-Specific Flood Strategies
Mission 6: 343 Guilty Spark
First Flood encounter. The shock factor is the real challenge. Shotgun + AR loadout. Take your time — this mission teaches you Flood behavior.
Mission 7: The Library
The ultimate Flood endurance test. Endless waves in tight corridors. Shotgun is mandatory. Retreat, shoot, reload, repeat. Memorize health pack locations.
Mission 8: Two Betrayals
Three-way battles — Flood vs Covenant vs You. Let them fight each other whenever possible. Pick off survivors.
Mission 9: Keyes
Flood-infested Covenant ship. Confined corridors with Carrier Forms around every corner. Methodical room-clearing is essential.
Frequently Asked Questions
Are the Flood scarier in the remake?
The original Halo CE's Flood were genuinely frightening for their time. With Unreal Engine 5's rendering capabilities, the remake could make the Flood significantly more horrifying — imagine combat forms with detailed flesh textures, more grotesque body horror, and atmospheric lighting that makes the Flood-infested sections genuinely terrifying.
Why does the Shotgun work so well against Flood?
The Shotgun's wide pellet spread and extreme close-range damage match perfectly against the Flood's swarm-and-rush behavior. Combat forms rush directly at you — right into the Shotgun's optimal range. One blast destroys any combat form, making it the most ammo-efficient Flood killer.
Can the Flood use vehicles?
The original CE didn't feature Flood-controlled vehicles, though later Halo games introduced this. The remake may or may not include vehicle-capable Flood forms.
Do Flood ever fight Covenant?
Yes! In Missions 8 (Two Betrayals) and 9 (Keyes), you encounter three-way battles between Flood, Covenant, and yourself. Letting them fight each other is a valid and often smart strategy — conserve your ammo and clean up the survivors.
How do I know if a body might reanimate?
Infection Forms seek out corpses to reanimate. If you see small Infection Forms swarming a downed body, it may rise as a Combat Form. Destroy corpses proactively — a Shotgun blast to a body prevents reanimation.