Here is the full list of all 36 Trillion: God of Destruction achievements.
Defeated Trillion in its Dragon Form!
Amassed a variety of Passive Skills!
Got 100,000G!
Began a second playthrough!
Defeated Trillion in its Titan Form!
Inflicted 10 billion damage with one hit!
Defeated Mokujin with one hit!
Completed all entries in the Gift Guide!
Used every Death Skill!
Strengthened a weapon by +10!
Reached the MAX level in a relationship!
Leveled up a skill to the max!
Gave someone the best present ever!
Executed Double-Up for the first time!
Retreated for the first time!
Unlocked "Holy Illusion"!
Broke through Trillion's outer armor!
Gave a present for the first time!
Executed Fever Time for the first time!
Used Interact for the first time!
Used Order for the first time!
Challenged the Valley of Swords for the first time!
Trained for the first time!
Powered up a weapon or opened up a slot!
Performed a stat increase for the first time!
Obtained every trophy!
Watched all the lovey-dovey endings!
Defeated Trillion with one of the first three Overlords!
Cleared Challenge Mode!
Watched the true ending!
Watched everyone's hot springs event scenes!
Affection Points have surpassed 1 billion!
Defeated Trillion in its Final Form!
Amassed a variety of Active Skills!
Opened up all the Demon Seal slots!
Strengthened a weapon by +30!