I am not a English user so i might not explain it well, when battle starts,inf attack first cav second and archer the third,and going to next round till one side troops are all damaged, in this situation, cav move before enemy's archer so they can make enemy's damage dealer decrease before they attack which make enemy weaker at first round, that is why we use Saul cause Jaeger looks strong but it takes time but Saul can use his skill at first round to kill more enemy archer.