You can play as the boss characters in multiplayer.

Bastille: complete raptor, mantid drone, and guardian's trial.
Syra: complete campaigner, Lord of the dead,and juggernaut trials.
Symbiont: complete Fireborn, Mantid mites, and oblivian spawn trials.
Tal'Set: complete Mantid soldier's Trial

Create a character and save it. Get 500 career kills. As soon as you have 500 kills copy that player to the other 3 slots on the save pack. Load all four people and your combined kill total will be 2000 kills. Now at the main menu hit "Z" and turn on the cheats you want.