Complex sentence: Silhouette is a Mutate not a mutant, the mutagenic source of her powers was the pan-dimensional leaking out of the "Well of All Things", this allows her to manipulate the Darkforce but on a more limited level that other Darkforce wielders in the Marvel Universe.
Split into simpler sentences: Silhouette is a Mutate, not a mutant, as the mutagenic source of her powers was the pan-dimensional energy leaking out of the "Well of All Things". This allows her to manipulate the Darkforce but on a more limited level than most other Darkforce wielders in the Marvel Universe.