Kasumi Nakasu

Kasumi Nakasu is one of the nine idols in Nijigasaki High's Idol Club. She is a first year and her image color is yellow.

As Kasumin loves all things cute, her unrivaled love for idols is strong and inspired. With the goal to dominate and become number one, she's a sore loser when she comes anything other than first place, even to the point of sabotage or cheating. She hates the nickname Kasukasu (かすかす) which roughly translates to "just barely" or "not quite", and gets in a bad mood when referred to with it. You'll often find her scheming or thinking up new ways to ensure her own victory; however, these plans often fail or aren't as devious as she thinks.

(Source: Love Live! Wiki)