Hostile mobs equipped with shields and sometimes defending themselves

Hostile mobs equipped with shields and sometimes defending themselves would make PvE combat more exciting. Currently, few players seem to use axe or crossbow in PvE combat. And PvE combat feels a bit rutted. When shield prevents an axe attack, there is a cool time to re-use a shield. So, If hostile mobs that use shields are implemented, there will be more options to use axes in PvE combat. Piercing crossbow ignores a shield,which increasing the chances of using crossbows in PvE combat.