Albus Dumbledore's gay lover.
"They (Dumbledore and Grindelwald) got on like a cauldron on fire" -Bathilda Bagshot
The first Dark Lord within memory in the Potter-verse. Described in the book as having golden curls and being quite good-looking, and was apparently young Albus Dumbledore's best friend with whom he plotted Muggle domination. Stole the Elder Wand (see HP 7: The Deathly Hallows), the least of the Deathly Hallows. Defeated by the same Albus Dumbledore that was his best friend.
Grindelwald was defeated by Albus Dumbledore prior to the second Dark Lord, Tom Riddle.