Okay, so Magnus Bane is from Cassandra Clare's 'The Mortal Instruments' series, a warlock who's been around for centuries. He's a bit of a flamboyant, chaotic energy sort of character, known for his glitter, snark, and dramatic fashion sense. His powers are pretty classic high-warlock stuff: he can do magic, obviously, like summoning demons, creating portals, casting glamours, and manipulating energy. He's also immortal, or at least extremely long-lived, which gives him a world-weary perspective that contrasts with his party-boy exterior.
What I find more interesting than the spell list, though, is how his magic ties into his character. It's often described as blue or gold, flashy and visible, which mirrors his need to be seen and his defiance against the more subdued Shadowhunters. His power also comes from his demon father, which is a source of internal conflict for him—it's a part of him he can't escape, linking him to a heritage he has complicated feelings about. The immortality angle feeds into his loneliness and his fear of attachment, making his relationships, especially with Alec Lightwood, way more poignant. Honestly, the magic is cool, but it's the way Cassandra Clare uses it to explore his isolation and vulnerability that makes him memorable.