Was Black Mantas Grandfather part Atlantian?

Rating: 8/10 (6 March 2019)

I want to say first that this movie is visually stunning! The acting is good, but the fight scenes and action sequences had me glued to the movie.
Ok, so here's one of my remaining questions. Follow me down the rabbit hole for a second. In the opening Russian sub scene Black Manta receives his grandfathers knife. Then while battling Aquaman, Black Manga tries to uses human made steel but can not injure him. After receiving the armor and confronting Aquaman, Black Manta reveals that he now has Atlantian steel. A few frames later he tries to wield his grandfathers blade on Aquaman and cuts him deep. So.....does Black Mantas backstory have an Atlantian connection?