Does he care for anything other than UNLIMITED POWA?
Immortality and in general discovering the intricacies of The Force and how to bend it to his will at a cosmic level. This turned into an obsession that almost drove him mad. Even his musings, the way he talks and carries him set him apart from a lot of Sith.
I’m not saying he’s the deepest character in all of Star Wars but for Dark Siders he is an anomaly.