Seems like they're preparing a new part of Time Temple.

My bad, I was referring to how he acts in Dissidia. But still, if everything includes yourself, then I pity the fool who wants all existance, even his own, to end.

I pity more the fanbases who are subjected to such tripe.

On another note, I do think that maybe Rhinne IS evil, and Black Mage is doing a Bakal - making us stronger so we can defeat the true enemy.

I have no idea who Bakal is (obscure, non-googleable references aren't helping), but absolutely nothing in the established plot would allow for the Black Mage to secretly be a good guy.

Maybe you'd have a chance if he was a newly rising threat, but this is the second time the dude has tried to conquer the Maple World. If there was a point for him to explain his alleged true motives, it would have been shortly after being sealed away the first time.

I mean, after all, if the game ended with Black Mage, Nexon KNOWS they're toast. So they either have to:

A)Create a story that branches off of the Black Mage's defeat

Or

B)Create an entire new threat to Maple World entirely (Since the original storyline concept of Masteria originally belonged to us, Naricain isn't allowed here, and sadly, neither are the Goetics.)

Or, you know, they could close their eyes, spin in a circle, and point to any fictional series and use whatever cliched method of universe perpetuation they used.

Among the infinity of choices:
- Create a filler arc in which some mysterious happenings are occurring and the players have to go investigate. Turns out to be a minor threat. If a really minor threat, this trope can be repeated until fans get tired.
- Have someone important disappear and they must be found.
- If the Black Mage is resealed, one of his loyal followers seeks to unseal him. Bonus points if one of the protagonists is tricked into helping.
- If the Black Mage is killed, one of his loyal followers finds a method to resurrect him, and the players must put a stop to the ridiculously elaborate ritual.
- Have a new threat appear, but, as the arc continues, reveal that the new threat is actually the Black Mage reincarnated.
- One of the Black Mage's generals takes charge of the army. All enemy uniforms are slightly altered.
- Vampires.
- A new enemy appears who is a significant threat, but will be defeated and subsequently alternate with the Black Mage every 'major' plotline.
- A new enemy appears who is a significant threat who, once defeated, will join forces with the Black Mage.

I'm sure I could think up more given the time.
This is not an 'either-or' situation.

Plus, for crying out loud, this is an MMO. How many bosses in this game have been defeated and subsequently disappeared?
There are no 'time-limited' bosses. Once you kill a boss once, well, you can go back and kill them again and again.

On a side note, I fail to see how the demons can't be allowed.

Anyways, Nexon won't simply end MapleStory on the Black Mage's defeat - evil is eternal, people just have no idea where to look for it.

Well, no pomegranate.
Your reasoning is wrong though.

Maplestory won't end on the Black Mage's defeat for the simple fact that the game makes them money.
It's the same reason some shows drag on forever despite the fact that the plot could have easily been wrapped up ages ago.