Mabinogi: Heroes will be another Korean MMO releasing soon in Spring 2008; however, this will be an action MMO running Value's famed Half-life Source engine!
From what we have seen so far, the game looks incredible as it appears to resemble an action hack and slash console game than a PC MMO. Environments are fully interactive, objects are destructible and can be picked up.

We were able to locate the high resolution trailer video. Right click the link and save as.
Mabinogi: Heroes Trailer 720p (1280x720)