Answer:
My first is in blood and also in battle. My second is in acorn, oak, and apple. My third and fourth are both the same. In the center of sorrow and twice in refrain. My fifth starts eternity ending here. My last is the first of last, Oh Dear.
It is sometimes known to have silver linings.
A kind of weather that comes your way, but add a "D" and it will run away
What comes once in a minute, twice in a moment, but never in a thousand years?
My first is in wield, sever bones and marrow. My second is in blade, forged in cold steel. My third is an arbalest, and also in arrows. My fourth is in power, plunged through a shield. My fifth is in honor, and also in vows. My last will put an end to it all.
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.