Calant felt his blood boiling as soon as he heard the words "legacy spell and I will crush it" in the same sentence.
A big force normally doesn't appear out of nowhere, years of accumulation, talented individuals, good management and luck, that's how strong families are built, although they might be some… exceptions.
A legacy spell is a spell that was created and has been perfectioned by at least twenty generations, if you add to that the fact that the lifespan of Arch ranks which tend to be the peak of strength for those of noble birth, can be counted on the thousands of years.
Then you can imagine how much thought, experimentation, review, redo and realization, does a legacy spell require, the result is often the foundation of a big family as there is an upgraded version of the same spell for upper realms.