Here is the full list of all 19 Heavenstrike Rivals achievements.
Train a unit.
Get a ★★★★★ unit.
Get a ★★★★★★ unit.
Get a ★★★★ unit.
Complete Story Mission 43.
Complete Story Mission 62.
Reach Level 10.
Reach Level 20.
Reach Level 50.
Complete Story Mission 21.
Complete a Strike Mission.
Complete a Daily Mission.
Promote a unit.
Reach Level 100.
Be promoted to Drake Division.
Be promoted to Chimera Division.
Be promoted to Basalisk Division.
Be promoted to Archangel Division.
Be promoted to Sky Ruler Division.