Ralf Jones - His swift melee attack can damage artillery and he can use his Vulcan Punch to rapidly destroy most enemies, but he only gets half the normal ammunition for weapons and grenades.
Leona Heidern (XX version only, via DLC) - She gets slightly-increased ammunition for weapons and grenades and extra durability when in Slugs, and can use a special Moon Slasher attack that can damage artillery and block projectiles.