The nature of predators is by far one of the most popular HFY stories, spanning several entries. One of the highlight alien species are the Arxur, a race of carnivores that start out as the primary antagonists. Would highly recommend. Trained on as many images I could find, should do males and females good.
Trigger phase: arxur_nop, alien, reptile, furry, grey scales, sharp teeth, slit pupils
Scar, or facial scar, usually look pretty good
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