Vongrak
Actually, Kat may just tick several of the powers ideal for a bodyguard. She has true sight which means no confusing her with illusion or invisible assassins... Lie detector doesnt hurt to have. She is near unkillable and perfectly okay mentally with putting her body between her ward and any threat or incoming attack. her mental and physical speed is also useful. She is largely immune to heat and cold and with her dreamwalking she could even enter the ward's mind to help them fight off a mental attack... Heck her calmness aura could be good for de-escalating a situation and her frostbite means less risk of collateral damage, can create barriers in a pinch and is overall better as a defensive tool than fiery flames would be.