MapleStory

Roles

Manager, Live Service Game Design
Design Coordinator
Data Manager
Quality Assurance
Customer Service (Technical)
Game Master

About (from Wikipedia)

MapleStory (Korean: 메이플스토리 Revised: Meipeul Seutori) is a free-to-play, 2D, side-scrolling massively multiplayer online role-playing game, developed by the South Korean company Wizet. Several versions of the game are available for specific countries or regions, and each is published by various companies such as Nexon.

Link

http://maplestory.nexon.net/

Level Design

While working on Maplestory, I've created 80+ levels. This image has a portion of that work demonstrated.

NPC & Quests

I've also handled the integration part of 30+ NPCs and 70+ quests. 
This image has a good portion of the NPCs I've added to the game. 
(Please note that the art themselves were drawn by the great 2D artists whom I had pleasure working with)

Monsters

I've attached a subset of monsters I've integrated in this gallery.
I've also handled balancing their stats, assigning drop rates, creating new attacks based on existing animations.

GM

I started as a GM. I had my fill of pleasure swinging GM hammer and designing hack prevention systems.