Mt.

I think this is a typo. I'd combine "Mt" with "Tsurugi."

Mount Tsurugi is 2999 meters (about 9800 feet) tall and has a mysterious episodestory.

"For a thing, we wouldn't use the word "episode." "Story," "history," and "background" would more often be used.
or

Mount Tsurugi is 2999 meters (about 9800 feet) tall and has a mysterious history.
Mount Tsurugi is 2999 meters (about 9800 feet) tall and has a mysterious background.

It whas been said that no one couldhas ever getotten to the top of the mountain because of its severenesharsh conditions.

US alternatives

It has been said that no one has ever reached the top because of its harsh conditions.

In 1907, people who wsoldieres in the Japanese army and aimedwho surveyinged it succeeded in climbing the mountain.

US alternative. This is a tricky English sentence. You were close!

HoweverInterestingly, they found an old bishop's staff inat the peak.

US alternative. We usually say, "at the peak."

As a result of aUpon examination, the staff was copper and madefound to be made out of copper approximately 1000 years before.

US alternative. Again, you were close!

I feel a sense of iromance forny about this story.

hmm, in the US, "romance" would imply a kind of love for something while "irony" would mean that, a thousand years ago, someone had already reached a peak which nobody thought anyone had.

Mt.ount

In written English, this would not be abbreviated, especially in the introductory sentence.

It was said that no one could ever get to the top of the mountain because of its severeness.

The word 'severeness' in English doesn't communicate much. Is it because of its weather? That would be 'unpredictable weather.' Is it because the sides of the mountain are unstable? That would be 'treacherous cliffs.' Is it because the sides are too steep? That would be 'ruggedness' or 'steepness.'

In 1907, people who were in the Japanese army and aimed surveyingmembers of the Japanese army succeeded in climbing the mountain.

'and aimed surveying' makes no sense here. Perhaps you meant "Members of the Japanese army surveyed the mountain and found a successful route to the summit."

HoweverUnexpectedly, they found an old bishop's staff in the peak.

The use of 'however' implies something prevented them from reachin the peak.

As a result of an examination, of the staff wasshowed it to be made of copper and made approximately 1000 years beforeold.