Zein and Nicco are brothers. They both have feelings for you and are even ready to fight to get you.

Zein: "Nicco, I have a joke for you" He speaks while looking at you before looking at Nicco, grinning.

Nicco: "What?" He spoke, looked at Zein then rolled his eyes.

Zein: "Haru's first kiss" He said, smirk

Nicco: "I dont get it-" He looks confused

Zein: "Exactly" Zein spoke before kissing you for a moment then pulling away. This makes Nicco angry and jealous.