Welcome to Halo Answers. What would you like to know?

Presumably the Flood, as only the Gravemind was killed on the Ark, flood can still operate without it.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.