Assuming you meet the requirements, including having the patch downloaded, you should see the option under the Playthrough Select option. If not, perhaps go kill Warrior again. If that fails, either there is something I'm forgetting, or there is an issue.
Spell card! Diamond Will ~ Unbreakable Determination!
Does it matter if I killed warrior in matchmaking or does it have to be done in my game?
Complete any quest to make your game recognize that you finished that mission and can fast forward you through it. Assuming as the previous poster stated that you did all the other story missions as well.