Man, trying to remember all the characters in 'Ishq e Junoon' is like trying to count waves. The core duo is obviously Dua and Ibrahim, whose whole enemies-to-whatever-that-was kept me hooked, though honestly Ibrahim's brooding act got old faster than milk sometimes. Then there's the best friend, I think her name was Farah? She was mostly there for Dua to vent to. The real scene-stealer for me was Ibrahim's stern father, Mr. Ahsan, whose disapproval was a character all by itself—you could feel the pressure he put on Ibrahim from across the page. Also, Dua's family, her mom especially, added that layer of tradition versus desire that defines so much of the tension.
It's been a minute since I read it, so I might be forgetting some side characters, like that one guy from Ibrahim's work who kept causing problems. The cast isn't huge, which works because the story zeroes in on that obsessive, all-consuming love (or whatever you want to call it) between the two leads. Everyone else basically orbits their drama.