The characters will act as a special CPU character that learns the more you play it making it a more difficult foe for you to fight yourself or use as an ally against friends. (allgeektome.net)
Moments like this are the perfect time to strike and kill even the most difficult foes. (xboxenthusiast.com)
Yuu will sometimes offer emergency missions, where you will be tasked with taking on a more difficult foe with greater rewards, and Shuusui allows you to undertake infinite battles. (gamingunion.net)