|Variants||Combat, Infection, Carrier, Juggernaut|
|First Encounter|| Season 1 Episode 19:
the flood are hostile aliens in the rise of the dark nemesis series.
the flood are an infectious parasitic race that use organic technology. although they seem to have no weapons, they use an enemy's own weapon against them. most of them tend to be found back on halo installation 03.
flood forms come in various shapes and sizes depending on the host it infects. their goals are currently unknown.
multiple flood forms can merge together to form stronger types. although they don't use tactical information, they rather exhibit feral and savage behavior. it is confirmed by judy hopps that the flood cannot be cured by any known means. they are also not allied with the imperials.
during the halo installation 03 incident, imperials accidentally released flood spores that infected them and other special imperials. the attacks were catastrophic, as they overwhelmed the imperial fleet.
on extreme rare cases, flood forms can become infected by the X-zeno virus, however this also causes conflicts between both the infection form and the virus itself. for an example, the virus wants to attack a combat form, but the infection form doesn't. this causes conflict for control of the body.
- in the remastered season 1 theme, captain jason fenix is seen dismembering a flood combat form's arm with a shotgun.
- although encountered only once in the series, they return in season 2 episode 18. aka: the flood returns.
- the lekgolo (or hunters) are immune to flood infection.