When going to your soldiers Customize place, enter any of the above first names and last names in the respective place(they must be spelled and capitalized correctly, but nicknames are automatically put in. Note that putting any of these heroes in the game disables achievements permanently(the game warns you), and disables customization for them. However, each of them come with the best of their class, but there equipment cant be used by other squad members or heroes until properly researched.

Effect	Code
Assault Class pre-equipped with Titan Armor, Alloy Cannon, and Plasma Pistol. HE haas 20 health, 100 aim and will	William Carter
Psionic Psi ArmorSupport wiht 20 hp, 200 will, 100 aim, and Mindfray, Psi Inspiration and Telekinetic Field. Also has Rift	Sid Meier
Rapid Fire Ghost ArmorAssault with 100hp will and aim(hp doesnt visibly go down until he takes 71 damage)	Otto Zander
Snapshot Archangel Sniper with 200 aim, and 110 will and 20hp(he has so much aim that he will never miss)	Ken Levine
Squadsight Ghost Armor Sniper with 100 aim will, and 20 hp	Chris Kluwe
Titan Armor Heavy with 20 hp, 100 aim and Will.	Joe Kelly