Major Story Arcs
Fear Itself: The Fearless
When Valkyrie sought to reclaim the Serpent's Hammers of the Worthy in order to keep them out the hands of those who would abuse their power, it was one of Host's spiders sneaking into Valkyrie's bag that allowed the D.O.A. to track her to where she hid the Hammers.
Powers & Abilities
As his name states, Host's body is host to numerous other living creatures, including snakes, scorpions, spiders, insects, and virtually anything else creepy and crawly. All these creatures obey his commands, attacking his enemies in swarms, scouting ahead, or even acting as living tracking devices for Host. The exact nature of Host's connection to his creatures hasn't been fully explored but it's presumably magic-based, given his membership in the D.O.A.