Here is the full list of all 32 Underworld Ascendant achievements worth 1,000 gamerscore.
Escaped Pluto's Gate.
Defeated 5 enemies without being damaged.
Enemies convinced to turn on each other.
Descended into Pluto's Gate.
Use the Wall Run skill along a 5-meter stretch of wall.
Cast a spell with 4 runes.
Kill a Bound enemy while time is slowed down.
Kill an enemy with a trap that had been blocked.
Avoid death 3 times with the Iron Shirt and/or Shadow Step skills.
Leapt a horizontal distance of 15 meters.
Acquire the Sun Abyssal Key.
Make a 5000-silver piece sale to Aelita.
Make a 5000-silver piece purchase from Aelita.
Collect 90 Compendium entries.
Deal 10000 total damage with ranged attacks.
Deal 15000 total damage with melee attacks.
Deal 10000 total damage with axes/maces/hammers.
Deal 10000 total damage with swords.
Deal 10000 total damage with daggers.
Quench 5 torches with water arrows.
Hide in the shadow cloud of a Deep Slug trail.
Deal 10000 total melee damage without weapons.
Deal 1000 total damage with each of swords, axes/maces, daggers, and unarmed.
Stopped Typhon -- but at what cost?
Brought harmony to The Abyss.
Saved The Abyss a second time.
Stay to the bitter end.
Completed "Abyssal Key of Upper Erebus."
Completed "Abyssal Key of Titan's Reach."
Completed "Abyssal Key of the Cytheron Catacombs."
Completed "Abyssal Key of Tyball's Folly."
Completed "Abyssal Key of the Underswamp."