User blog comment:B214/Talk About What You Want! 2/@comment-24173056-20140703114557/@comment-1359322-20140708022454

But remember, Sona had her entire team which was 8 people, while the Hero Faction only had 3, Jeanne, Heracles and Georg, in that sense, it would make Sona's group look cowardly too. So lets just say it's the flow of the battle.

After all, Cao Cao was facing 13 opponents alone, if he doesn't pull out some tricks i don't think it's possible for him to survive much less win. The same goes to the Hero Factions, Sona had more than twice the number of people in that fight, they should expect that the enemy will use some strategy or tricks. I guess it boils down to inexperience and overconfidence.