From Pathfinder Lost Omens Draconic Codex, which isn't enabled.

War Rider Stance

FEAT 6

Activity 1 action

Prerequisites Drake Rider Dedication; expert in martial weapons; dragon companion with a support benefit that includes damage

Your dragon's constant breath threatens your foes. While in this stance, your dragon companion has an aura in a 5-foot emanation. Each creature that starts its turn in the aura takes the damage listed under the dragon's support benefit with a basic Reflex save against your mount's Athletics DC.

Pathfinder Lost Omens Draconic CodexORC