Here is the full list of all 21 Ys SEVEN achievements.
Complete the game on Nightmare difficulty.
Obtain all other achievements.
Complete the game on any difficulty.
Unlock all bestiary entries for all non-boss, non-titano foes.
Synthesize all Dragon Stone weapons.
Learn every skill.
Conquer the Moon Dragon, Ze-Kalion.
Conquer the Sea Dragon, O-Balon.
Raise all of any one character's skills to max level.
Defeat all titanos.
Buy every item from the Zanzibar Firm.
Conquer the Wind Dragon, Mu-Anti.
Find all the missing pikkards.
Conquer the Earth Dragon, Rada-Manj.
Synthesize each Spirit Elixir at least once.
Conquer the Flame Dragon, Angue-Barl.
Survive against a beast intended specifically to kill you.
Defeat Geis in one-on-one combat.
Escort Tia back to Altago City completely unscathed, and without using any healing items.
Die by walking over thorns.
Die by drowning.