To unlock you must simply complete the story mode beating all eight opponents using Cinder on any difficulty earning any objectives.
If you want progress towards :
He has three objectives, and all can be completed in one run.
1) Beat story mode. Simply win all eight fights.
2) Ultra combo every opponent. See number 3.
3) Ultra combo Glacius. Simply beat Glacius with an Ultra in the seventh fight. His ultra is
when Glacius's health is reading 'danger'.
Ultra every opponent like this to earn objective number 2.