A quick web search didn't really give me any ideas as to "spell-like" powers they might be associated with. I got more of the impression that their power was internal. Based on that, it seems as though a greater reliance on non-spell powers would make sense: strength, toughness, wings, breath, claws, etc. Perhaps they have magic, but the magic is largely Biomantic in nature, allowing them to make their best warriors larger, faster, stronger than they would naturally be? Perhaps ritually eating a fallen foe's organs counts as a form of blood magic, powering a ritual that makes them more powerful (sort of a mini-ascension rite)? They might also have a few priests/shamen/whatever who have something that is closer to 'normal' magic, though these would appear far more runtish than the warriors, as their magic is focused outward. I imagine they would focus on rather unsubtle aggressive spells.
You might also look into Warhammer's Lizardmen for ideas. For example, you might have different species of reptiles -- perhaps with Dragons as the warrior/nobility caste, and others breeds playing lesser roles down to Skink-like slaves as dim, expendable grunts.