A Blue Frog is a member of the Church of the Blue Frog, a faction in NEO Scavenger. The group is led by King Elias, with their main outpost located at Saginaw Mental Institution.

All members of the Blue Frog cult are carriers of the deadly disease known as the Blue Rot. The Rot can be contracted by staying too close to the infected person (varyingly up to range 4 and closer in combat) and the closer the player and the carrier are, the bigger the chance of the infection spreading. It is generally good practice to use ranged weapons (or thrown weapons, like spears) against Blue Frog members, in order to avoid the disease. Wearing a gas mask with charged cartridges will also prevent contraction of the disease. Wearing a rag (clean or dirty) on the mouth will also provide limited protection.

Blue Frogs generally have the Tough and Strong skills, as well as being trained in Melee and Ranged combat. As with other human characters, Blue Frogs are known to carry weapons and will actively track the player or other NPCs, often form raiding parties. They harbor a particular hatred for ATN Warriors.

Blue Frogs are hostile towards non-believers. Spurred by their religious zeal, they will usually attack on sight. Blue Frog Preachers can be easily recognized by the distinctive equipment they wear: a hospital gown, a blue sash and a gas mask.

Occupying the same map hex with an infected Frogger, outside of combat, does not carry a risk of infection. During some random encounters, the player may find several members of the Blue Frog cult, usually in non-combat situations. Be warned, though, as the player may contract the Blue Rot from close contact during these encounters.