Here is the full list of all 23 Umineko When They Cry - there are Answer Arcs achievements.
Something’s different this time...
Battler jumps out Kinzo’s window
Complete EP5
Complete the EP5 Tea Party.
Complete the EP5 Hidden Tea Party.
They cannot save you.
Complete EP6.
Complete the EP6 Tea Party.
Complete the EP6 Hidden Tea Party.
And so, the tale begins.
Complete EP7.
Complete the EP7 Tea Party.
Complete the EP7 Hidden Tea Party.
Get every medal.
Find the culprit without any hints.
Ending A reached.
Ending B reached.
Complete the EP8 Tea Party
Complete the EP8 Hidden Tea Party
Master EP5-8.