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