Magic Crest

An inheritance passed down within magi families.
The mysteries that a magus has spent his entire life establishing (stabilizing) are turned into a crest and left to his descendants.
It's no exaggeration to say that the crest is engraved with the history of the entire bloodline, and that the magus who inherits it is burdened not only with his family's regrets, but is duty bound to pass it on to a successor as well.
In a way, you could call it a curse passed down through the generations.

Fate/side material: Fate Encyclopedia