Thunderbolt

To understand why the Elven Kingdom wanted to gain control over the Haiga Mountain Range, one had to start from the Great Escape after the Dark Age. Back then, the Goddess of Forest Monferra created a miracle—she made the Haiga Mountain Range to help the elves escape from human troops¹. Hence, the Haiga Mountain Range was a sacred mountain range to the elves starting several hundred years ago.

Every elf wanted to get back the sacred mountain range, but the Elven Kingdom was weaker than the two human kingdoms in every aspect. These two human kingdoms didn't give it their all, but the Elven Kingdom failed terribly even after doing so.

The reason why they failed was rather funny.