Here is the full list of all 25 Bastard Bonds achievements.
Obtain a Devil Adonis.
Ruin a powerful weapon.
Earn someone's trust.
Let someone down.
Restore the proper flow of time.
Save Captain Logus.
Complete the Eccentric Smith's project.
Have an audience with a Demon Lord.
Destroy Leviathan and escape from Lukatt
Pacify Leviathan and conquer Lukatt.
Reconnect the estranged couple.
Obtain the darkest arcane power.
Decide who wins the contest.
Find the acoustic sweet spot.
Vent about past regrets.
Rescue a hapless friend.
Get left out of a game.
Forge the brothers' emblems together.
Disrupt a shady business operation.
Teach a friend some proper manners.
Don't let anybody sleep on the floor.
Tear open an old wound.
Sooth the fears of a monster.
Attend a friend's second wedding.
Second-Guess a friend's history.