Here is the full list of all 38 Krzyżacy - there are The Knights of the Cross achievements.
Complete Forest Child
Complete Gentle Giant Axe
Complete Holy Light Guardian
Complete Female Knight’s Growth
Complete Miracle Arrow
Complete Wish Comes True
Complete Whisper of Hope
Complete Deadly Twin Tails
Complete Reliable Friendship
Complete Sea Breeze Blows
Complete Challenge of the Strong
Complete Knight and Rose
Complete Good Luck Descends
Complete Great Inventor
Complete Capricious Blessing
Complete Starlight Guidance
Complete Priceless Friendship
Complete Blooming Anemone
Complete Poison that Helps
Complete Overwhelming Persuasion
Complete Gentle Elder Sister
Complete Will of the Sword
Complete Businessman
Complete King's Demeanor
Complete Guide
Complete Iron will
Complete Contacts and Shield
Complete Sea of Knowledge
Complete Worldly Priest
Complete True Salvation
Complete Guarding Wilno
Complete Knights and Oaths
Complete Proven Innocence
Complete Beauty and Beast
Complete Belief in Salvation
Complete War is Coming
Complete Final Battle of Grunwald
Complete Encounter Guided by Stars