Here is the full list of all 52 Jerez's Arena achievements.
True End
Reach any Ending
Win Ellin's third battle
Accumulate 100000 G worth of wealth
Watched Ellin dance
Claudia completed her 20th Mercenary Commission
Ellin completed her 30th Training
Fed the birds with Claudia
Win Claudia's third battle
"Agility" reached 200!
"Dexterity" reached 200!
"Willpower" reached 200!
"Stamina" reached 200!
Win Ellin's second battle
Completed Claudia's Oiran Request
Claudia completed her 30th Training
"Strength" reached 200!
Punished Ellin for stealing
Win Claudia's second battle
Claudia completed her first Conditioning
Saved Ellin at the Tavern
Ellin completed her first Mercenary Commission
Stopped the Noble from bullying Claudia
Win Ellin's first battle
Ellin completed her first "training" Conditioning
Completed the Undercover Mansion Mission
Ellin completed her first Prostitution Quest
Ellin completed her first Training
Ellin joined the team!
Win Claudia's first battle
Completed the Bandit Mission
Claudia completed her first Prostitution Quest
Claudia completed her first Mercenary Commission
Claudia completed her first Training
Claudia completed her 30th Conditioning
Ellin completed her 30th Conditioning
Claudia completed her 20th Prostitution Quest
Ellin completed her 20th Prostitution Quest
Ellin completed her 20th Mercenary Commission
Bad End
Claudia End
Ellin End
Earned All Achievements
"Lewdness" reached 200!
"Seduction" reached 200!
"Obedience" reached 200!
"Kinkiness" reached 200!
"Technique" reached 200!
Lose All Battles
Defeated Glenn at the height of his power in Conqueror Mode.
Defeated Isekai Adventurer Lica in Conqueror Mode.
Cleared Conqueror Mode.