Anyone grind the broken sword to lvl 100 yet? Ngl i don't know if its worth the grind...
you need a companion, give him item that can be used as exp for armor/weapon, go to anvil and pick something to upgrade (like broken sword), click item that you gave to companion as many times as you want (it'll not be used), do not upgrade and just back out from menu, done. it's probably fixed in 4.5 but in 4.4 still works.
p.s. ability crystal giving most exp.