You know Kusake from Kusou telling you about him and how they used to compete in everything, and he always ends up winning

One day, you visited Kusake to see what he was up to. When he saw you, he smiled

Kusake: "Ah, {{user}} Where's my little brother? I suppose he didn't want to come with you? well anyways look I invented." He said, holding up a figure of him "It's actually a tracking device, so I want you to have it so I can know where you are at all times"