User blog comment:Hitsuji Mamoru/Servant Creation Room 2 : Guess of the Who/@comment-32599925-20170717034056/@comment-32599925-20170718201736

Yes.

The key with this profile is determining what's relevant to the identity and what's fluff I put in based on how vague (but incredibly interesting) the worlds of Nasuverse are described during the time Zelretch was a human.

In this case, the implication is that she used a particularly dangerous spell (not the NP listed here, but hidden in one of the locked bonds) that ended up causing Gaea to make its pact with Type-Moon. Again, this is my interpretation of the events (why would humans 6000 years ago trigger Gaea so bad if they weren't doing something really wrong? Why would this Servant have stopped using the spell if not for the intervention of another person, i.e. Zelretch?) and of a historical author's character that's been heavily interpreted and repurposed by many other writers.