The true name, which only the Cohanim knew, was 216 letters long

Rabbi Cohen:

[a group of Kabbalists, the Rabbi speaks to Max]
The Talmud tells us it began 2,000 years ago, when The Romans destroyed the second temple. Maximillian Cohen:
What is this? Rabbi Cohen:
Max, you will understand everything if you listen... The Romans also destroyed our priesthood, the Cohanim. And with their deaths, they destroyed our greatest secret. In the center of the temple was the heart of the Jewish life, The Holy of Holies. It was the earthly residence of our God. The one God. It housed the Ark of the Tabernacle, which stored the original ten commandments which God gave to Moses. Only one man was allowed to enter this Holy of Holies on one day, the holiest day of the year, Yom Kippur. On the Day of Atonement, all of Israel would descend upon Jerusalem to watch the High Priest, the Cohen Godul, make his trip to The Holy of Holies. If the High Priest was pure, he would emerge moments later and we were secured a prosperous year. It meant that we were closer to the Messianic Age. But, if he was impure, he would die instantly and It meant that we were doomed. The Holy Priest had one ritual to perform in The Holy of Holies, he had to intone a single word... That word, was The true name of God. Maximillian Cohen:
So? Rabbi Cohen:
The true name, which only the Cohanim knew, was 216 letters long