His brothers will always help you,
Slaying spiders or golems.
Sometimes you see him for real,
Depending on how you live.
And the thing you won't believe,
Is that he can melt steel.
Even if he looks like a gem,
One day he will crush you.
Who is "he"?
hint 1 (kinda big one) :
He will crush what is left of you, if there is something left by that time!
hint 2 :
Line three is more of a joke than a real sentence and may concern Stack users :)
hint 3 :
the two first lines refer to a video game
last hint :
A very famous guy died trying to reach it