Skeletal Warrior is one of my most used cards. I really like to use this card and l won lots of teams with this card even when opposite team had higher level cards then mine. Best modes to use this card in my opinion are sneak mode, only melee monsters can be used mode, melee monsters can attack from every position, standard battle, little game mode etc. It's the best card to use in sneak mode because this card just cost 2 mana and he has 3 shield, shield ability to protect him from range and melee attacks which sounds incredible for 2 mana monster. You can also put this card at first position if you want to save your other tank time.