What kdrama is this??

This is going to be lowkey very vague but i remember i watched a kdrama about 5 years ago and this is what i remember. i mostly liked it cos the villain was hot.

• so the villain was the best friend of the main character ORRRR the perfect assistant to a boss
• he was known for being super sweet and kind to everyone in his workplace
• there was a scene where he wore like a hockey mask and beat up a guy to death using a hockey stick
• (this might be wrong) but the villain had curly hair i think.

yes. if anyone can somehow figure this out i will love u.