From left to right: Yuno, from Mirai Nikki, Shirayuki Mizore, from Rosario+Vampire, Komori Kiri- Sayonara Zetsubou Sensei, Hitou Nami - SZS, Horo- Spice and Wolf, Shana - Shakugan (gen? can't remember) no Shana, Louise - Zero no tsukaima >>12449333
The thing is, you're looking at Tsundere as one single set of personality traits. The point of the scale is to show that neither Tsun nor Yan are specific traits, but rather extremes of a scale which pretty much any relationship could fit into; Horo's is no exception. That doesn't mean the relationship is simple by any means: I fully admit that this could be a vast generalization in some respects. But it would still hold.