In MM6 there's a huge tower/spire thingy just west of Castle Ironfist. I've walked around it, flown up it, and yelled at it. What am I missing here?

you mean the mountain? doesn't do anything, might be a landmark for uhhh certain something tho

There's a small island just west of the castle with a sword in a stone and a feature that is so tall I can't reach or see the top. Is that what you are referring to as a mountain?

yeah that thing, think you might be able to top it with the jump spell. think it was too high for the fly spell though.

Maybe it was a feature they originally planned for the game but in the end couldn't include, so they just put the landmark in for fun. (That's certainly been done before.)

Or maybe they just wanted an allusion to the Arthurian sword in the stone legend, since King Arthur stories have had so much influence on modern fantasy.

I can't find any reference to it anywhere. How is this possible? The thing is too damn huge to serve no purpose or not have some importance.

spoiler

I do think it's a landmark for one of the very last quests in the game but I'm not completely sure if it is or not.

Iirc, you can pull the sword from the stone if the active character has enough strength. There are several of these swords-in-stones, requiring different amounts of strength. The swords generally aren't very good, though.

Edit: I just kicked up a new game to have a look. You can indeed pull the sword if the active character has enough strength. I don't recall that particular spire being relevant to anything at all (I didn't even remember it existing). There might well be nothing at the top.

Finished the game. That damn huge ass thing never came up in any quests or conversations. Giving its proximity to the castle, I've decided to pay homage to Prince Nicolai and dubbed it Nick's dick. My knight decided to commemorate the occasion by pissing on it. I feel better now knowing it finally has a purpose.

After that, the real thing will certainly be a letdown. And if that's his dick, are we pulling a sword/thorn out of his ball?

As for pissing, maybe Nick is into water spo.. I mean, water magic.