For those who don’t know. R’ Doniel Frisch ztz”l was the mechaber of the Matok Midvash peirush on the Zohar that is mekubel by all of klal yisroel.
I met him in Rav Gamliel Rabinowitz’s (one of the roshei yeshivah of Shaarei Shomayim of Rav Shlomo Zalman) house. He told me Rav Frisch was his rebbe and they were learning together.
He was niftar about 5 years ago or so and he was definitely one of the semi-hiddin tzaddikim of the past few decades.