Here is the full list of all 43 Hellslave achievements.
You finished HellSlave. Do you dare try the Inferno mode?
All 6 Infernal Demons have been defeated. You can now challenge the Anti-King of Hell.
A strange Archon was guarding the forbidden fruit.
You listened to all the whispers from the anomalies.
The Fallen Angel has been sent back to his fiery prison.
You entered Hell. Run away, you fool.
Leviathan's lightning will no longer disrupt this world.
Mammon, the Misanthropic Tyrant, swallowed his disdain along with his entrails.
You inflicted an average of at least 30 damage per second.
The Priestess of Lust has gone back to the hell from whence she came.
You discovered the salt steppes east of Nivlatth.
Your blows killed Beelzebub, Lord of Violence.
You crafted at least one of Simeon's items.
You defeated Baal, Master of Lies and Plague.
You crafted at least one of Bisith the Mage's items.
You crafted at least one of Zurgul's items.
You crafted at least one of Septhon the Aesthete's items.
You crafted at least one of Pegrarch the Pious's items.
You crafted at least one of Jacquor the Ingenious’s items.
You crafted at least one of Kamixiarisocl Iperpeniomicidus's items.
You crafted at least one of Balam's items.
You crafted at least one of Arbus's items.
You crafted at least one of Bisith the Unhinged's items.
Refrain from listening to the whispers of these ungodly weapons.
You crafted at least one of Septhon the Madman's items.
You crafted at least one of Pegrarch the Insane's items.
You crafted at least one of Jacquor the Exiled's items.
You crafted at least one of the strange Frail Servant's items.
After a tremendous effort, you've crossed the red line of humanity. Here's your reward.
You collected all the recipes and notes in Lore.
You finished HellSlave in Inferno mode. You've proven your worth.
You inflicted an average of at least 90 damage per second.
You inflicted an average of at least 120 damage per second.
You inflicted an average of at least 170 damage per second. That's a lot.
You made all of HellSlave's recipes. It probably won't help you seduce any potential lovers, but props to you.