The Fire Splinter has several good cards in addition to Serpentine Spy that I like to use (for example, Fire Elemental, Pyromancer, Ettin Spearman, and the summoner, Qid Yuff) but the one I use the most is Living Lava. Its Shield ability is especially good in low mana battles when many people use several small monsters with 1 attack (hey, when your in Bronze level, your choices are limited).