This would be a female character with Cryo ability. Basically, she will be a master of cold. Slow down enemies, freeze enemies or something like an ice shield. My initial thought of one of her basic abilities is like that of Aurelia “The Baroness” (borderlands series), where she would shoot a cryo shard that does cryo dps to an enemy. I say for here though, it would be a certain amount of time, not until they die. dont want her too OP (she could clear a room with ease)
she could have the ability to recover some health while the cryo dps is happening when shooting said enemy. and have a chance to freeze and enemy for an x amount of time. something like 5 seconds or something. single cryo damage as a first skill, and then a group one for the second skill. one that would do cryo damage in a bigger area and affect multiple enemies, and still have the chance to slow them down or freeze em.
again, this is just an idea as we have seen fire and poison damage in game.