Gelert Grindlewald was in the school Durmstrang he met a boy named Albus Dumbledore they were best friends and may even had fallen in love. But Gelert was expeled from Durmstrang and at the time the pair was enseperable and made a promis to get the hallows and become the best wizards of all time. They were sucsesful for they had the stone and the wand but as time grew they grew sick of eachother for one event happend. A dule between Albus, Aberforth, and Gelert broke out and in the process Arianna was killed and noone knew who casted the spell but they all went their seperet ways after that. Gelert lost his eye sometime through the years and replaced it with an eye that was a hallow. It saw under the invisibility claok that the third brother had gotten from Death. The eye could see through anything and it was the same eye that Mad Eye Moody would were in the generation of harry potter.