Cronus is a fairly standard Wind-based Attacker with.. kind of an attack-leech(it debuffs the target's damage while boosting hers). Passive looks like an attack boost.
Kaiser Dragoons come in all elements. 8-turn wait before summoning. Each one hits quite hard while amplifying the party's damage of their element and a resistance buff against whichever element they're strong against(Wind boosts resistance to Lightning, Water boosts resistance to Fire, etc.). Passives are scaling buffs for their respective element.