Pilot, your Titan is ready, prepare for Titanbombs
(02-23-2014, 06:55 PM)
I believe Respawn mentioned the following in an interview but just in case I'll spoiler tag them. I don't think they are really spoilers though.
I found these a few days ago but didn't post.
Unlocked by completing the IMC or the Militia Campaign.
Unlocked by completing both the IMC and the Militia Campaign.