Saw this over on DreamCancel's front page.
Youtube user 4b101 has been uploading quite a lot of KOFXIII combo videos and loads of characters are covered.
This Raiden combo i found particularly interesting:
What's worth noting about this is you can see one of the dropkicks is not fully charged, and not used until towards the end of the combo.
So this means basically this combo can possibly be performed during a match whilst charging one drop kick, and from what i've heard a Raiden player who charges only one dropkick during a match is far more deadly.
Anyway as mentioned there are loads more on his channel, check them out and subscribe for when he uploads more.