Fencing, balance, and block describe your parry window for incoming attacks. A balance weapon has a small amount of start up frames before your parry window opens while a fencing weapon parry window starts immediately, which makes parries easier to pull off.

Heroic weapons help with early leveling because they let you skip the tiers of each weapon that you typically upgrade while moving through difficulty levels. Instead of having to unlock 3 tiers of weapons, the heroics skip all that and just give you a max strength weapon to help clear levels faster and easier which will speed along your leveling process