Alredy bound to be conjuring stone...who says that? Maybe Elric was bound to be conjuring stone in dot arena?
Elric in Conjuring Stone??? No, NO and Hell NO!
He is Reload Hero for sure(Not Conjuring Stone like Vulko and Lars) but later to be one of CoF loot rewards...
Some are already bound to be Conjuring Stone in all platforms (Vulko and Lars), some are changed up by Developer means (Jasmine, Sylphi) and some of them is meant to be free hero instead of paying Real Money (Elric)
But all are decided from the Publishers itself (depends on how OP that Hero in Arena/Raid/HoL)