Here is the full list of all 49 Demonicon - there are The Dark Eye achievements.
Sacrificed yourself as First Paladin
Returned to Moloch Mountain
Destroyed the New Church's Catechism
Defeated Azaril
Denied Calandra
Acknowledged father and thereby chosen humanity
50 potions or poisons used
Freed father from imprisonment
Killed Cassio and sacrificed her blood
Banished bandits
Taifelel defeated
Gave Ulev the talisman
Led the Fernfielders to their fate
Defeated Ghamat and the Plague Maw
Cast 200 Gift spells
Defeated the Iribaar's Lily and yourself
Raised an attribute to its maximum
Reached Level 7 in one Adventure talent
Killed 10 enemies solely with Ranged Weapons
Successfully dodged two hundred times
Suffered the pain of Rondra's prescence
Convicted and killed Falk
Used 200 combat moves
10 potions or poisons used
Defeated the overpowering Heshthot in the market
Spoken to Borbarad's Council of the Dead
Caught the summoner in the Praios temple
Completed 5 battles without a scratch
Became member of the City Guard
Reached Mastery Rank Four in one talent
Killed Borak the Bruiser
Passed a Talent test
Spared the cannibal in Moloch Mountain
Achieved a chain of 24 blows
Received the Gift in the tutorial
Achieved a chain of 12 blows and triggered Demonic Fever
Learned Chain of Blows
Killed the cannibal in Moloch Mountain
Became member of the Kreutzer Cartel
Gave Genla the talisman
Banished guards
Slept with Calandra
Introduced the Catechism to the New Church
Sacrificed Calandra as First Paladin
Played Demonicon through without using a single healing potion
250 potions or poisons used
Acknowledged Seghal and thereby chosen the Gift
Played Demonicon through in Nether Hellish difficulty
Played Demonicon through in Hard difficulty