While Alec should be one of the scariest villains in the Twilight saga, the movie adaptations of the best-selling novels never delved deep enough into his disturbing powers. Twilight’s movies may have been incredibly accurate to the source novels, but the screen adaptations of the saga still inevitably needed to cut some details from the original novels for the sake of maintaining a reasonable runtime. Since many viewers were mostly interested in the love triangle between Bella, Edward, and Jacob, often, the Twilight movies cut elements such as villain backstories and other tangential information.

https://screenrant.com/twilight-alec-vampire-powers-explained-wasted/