Augment of Patron Magna (Hexblade)

(this replaces the Accursed Specter ability)
You can no longer curse the souls of a person you slay. Instead once per long rest when you or an ally is reduced to 0 from a hostile source if you don’t already have a Pegasus at your aid a pegasus appears and comes to your aid. When the Pegasus appears, it gains temporary hit points equal to half your warlock level. Roll initiative for the Pegasus, which has its own turns. It obeys your verbal commands, and it gains a special bonus to its attack rolls equal to your Charisma modifier (minimum of +0).

The Pegasus remains in your service until you dismiss it as a bonus action, it’s hp reaches 0, or after a long rest. It is returned to its celestial home.