I used this achievement guide from WikiGameGuides. He shows where all 10 dragons are and he also gives the amount of HP they have(He was playing on nightmare difficulty)
0:00 Ferelden Frostback - Hinterlands - Level 12, 105k health
0:56 Northern Hunter - Crestwood - Level 13, 118k health
1:39 Abyssal High Dragon - Western Approach - Level 14, 135k health
2:58 Gamoran Stormrider - The Exalted Plains - Level 15, 150k health
3:57 Greater Mistral - Emerald Graves - Level 17, 188k health
4:41 Vinsomer - Storm Coast - Level 19, 226k health
5:52 Sandy Howler - Hissing Wastes - Level 20, 246k health
6:33 FINAL 3 Dragons
6:59 Hivernal - Emprise du Lion - Level 19 , 226k health
7:32 The Kaltenzahn - Emprise du Lion - Level 21, 267k health
8:03 The Highland Ravager - Emprise du Lion - Level 23, 311k health
(before you give me a "thumbs down" on this or any other solution. Tell what I can do to fix it)
