Why is an Adamantine Armor a magical item while a Adamantine Weapon is just one made with a diferent material?

Find Greater Steed: when I summon a pegasus and mount it, is it controlled or independent?

“Orcish Fury” from Xanathar’s Guide is a bit confusing when it comes to crits

Xanathar miniature!

What about replacing the net damage with a monk weapon’s damage die as a kensei weapon?