User blog comment:OH&S/Toaru Majutsu no Index VS Durarara!! Special Collaboration/@comment-15657817-20160331024142/@comment-15657817-20170209074527

so in other words it's possibly referential in a purposeful way? I know design similarity is nothing new in anime, but Kiyama and Nasujima's resemblance is pretty startling. Mugino being added to the pile is also weird. That being said, again, it's easier to draw faces similar to ones that've already been drawn, rather than creating a new design. Oikawa Tooru looks like a young Nasu as well. Maybe it's just the 'brownish' wavy hair and foxish eyes, and in Kiyama's case, the eyebags, tipping me off?