Echo der Didaktikerin (Didact Echo)
Echo der Didaktikerin 

Abstieg 4 — Das Echo der Didaktikerin hat Flugfähigkeit, solange dein Friedhof vier oder mehr Permanent-Karten enthält.
Regeltext (Oracle, Englisch)
Descend 4 — This creature has flying as long as there are four or more permanent cards in your graveyard.
Das Volk des Imperiums der Sonne respektiert seine Ahnen. Die Oltec gehen noch einen Schritt weiter und kommunizieren mit ihren verstorbenen Ältesten.
Legalität
Regelhinweise (auf Englisch)
2023-11-10
Cards with the ability word "descend N" have abilities that care if you have at least N permanent cards in your graveyard.
2023-11-10
Some descend triggered abilities include intervening "if" clauses (i.e. "if you have [four or eight] permanent cards in your graveyard" in the middle of the ability). Each of these abilities checks your graveyard at the moment it would trigger to see if it does. If you don't have the required number of permanent cards in your graveyard at that time, the ability doesn't trigger at all. If it does trigger, it will check again as it tries to resolve. If you don't have the required number of permanent cards in your graveyard at that time, the ability won't resolve and none of its effects will happen.