Full list of all 52 Ruined King: A League of Legends Story achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Acquire 100,000 Gold (cumulative)
Complete Windrake Island
Defeat Possessed Gangplank
Defeat Thresh
Consume 50 Potions
Eat 15 Meals at Rest Points
Return Maokai to full strength
Unlock all Champion Ultimate Abilities
Acquire 200 Black Marks (cumulative)
Complete 5 Bounty missions
Unlock a Level 3 Ultimate Ability
Complete 50% of the Bestiary
Infuse 30 Items
Catch 100 Fish
Collect 50% of the Lore entries
Have Ahri join your Party
Meet Maokai
Have Pyke join your Party
Arrive at the Shadow Isles
Have Miss Fortune join your Party
Complete 50% of Baron's Rest Crucible battles
Infuse 10 Epic Items
Complete a Bounty mission
Complete 25% of the Bestiary
Cleanse Grey Harbor from Black Mist
Enchant your first Item
Reel in a Treasure cache while fishing
Have Yasuo join your Party
Consume 10 Potions
Meet the Rumor Monger
Team up with Braum
Experience visions of Ruined King
Complete all Bounty missions
Infuse 10 Rare Items
Enchant 30 Items
Catch 10 Epic Fish
Catch every type of fish and complete the Fishing Journal
Complete the story on Story Difficulty
Complete the story on Normal Difficulty
Complete the story on Veteran Difficulty
Complete the story on Heroic Difficulty
View every character dialogue when at Rest points
Unlock an alternate Skin for any Champion
Unlock all alternate Skins for all Champions
Complete 100% of the Bestiary
Complete all Baron's Rest Crucible battles
Reach Level 30 with any Champion
Pass the Test of Nagakaborous
Collect 5 treasures from Poro Holes
Collect all unlockable Lore entries
Acquire 1 Legendary Weapon
Acquire all Legendary Weapons