The fourth representative for the school was a fourth-year girl named Venessa, who Kain was the least familiar with. He hadn't had much opportunity to interact with her in the past and even during the beast-tide she was consistently located at a further distance away from them, therefore he'd only gotten a sense for how strong she was within the past couple of months.
The reason that Venessa kept a distance from them all during the beast-tide was due to her contracts all being poisonous—likely the poison-attribute being a necessary requirement of her affinity.
Not to mention she herself rarely stays within close proximity to others due to the nature of her gift.
Honestly, when Kain had first heard about her gift, while he admired its powerful abilities, he also couldn't help but feel extremely sorry for her.