Unlocking the platinum trophy in Elden Ring requires a strategic approach to ensure you collect all the necessary trophies in a single playthrough. Here’s a detailed step-by-step outline:

### 1. Understand the Trophy Requirements
– Total Trophies: 70 trophies are required for the platinum trophy.
– Offline Trophies: 42 trophies can be earned offline, while 28 trophies require online interactions.
– Missable Trophies: 5 trophies are missable, including the “Legendary Armaments” trophy for the Bolt of Gransax and the Lichdragon Fortissax trophy if you kill Fia before the boss fight.

### 2. Plan Your Playthrough
– Save Game Backups: Make sure to save your game before major milestones, especially before interacting with the final boss, to ensure you can unlock multiple endings if needed.
– Build Strategy: Choose a build that allows you to efficiently farm resources and tackle challenging areas. Using co-op summoning and spirits can make the game less difficult.

### 3. Early Game Progression
– Reach Roundtable Hold: This is a required location for several trophies. Traveling to Roundtable Hold earns you one of the “Gimme” trophies.
– Defeat Shardbearers: Defeating Shardbearers like Godrick, Radahn, Morgott, Rykard, and Malenia earns you silver trophies. These are crucial for progressing through the game and unlocking other trophies.

### 4. Legendary Loot Collection
– Legendary Armaments: Collect all nine legendary weapons. The Bolt of Gransax is missable and can be dropped by another player, but it’s recommended to find it yourself for consistency.
– Legendary Ashen Remains: Acquire all six legendary ashen remains. These are essential for upgrading your character and unlocking specific trophies.
– Legendary Sorceries and Incantations: Collect all seven legendary sorceries and incantations. These are crucial for completing various quests and achieving specific trophies.
– Legendary Talismans: Acquire all eight legendary talismans. These provide significant buffs and are required for several trophies.

### 5. Boss Trophies
– Shardbearer Bosses: Defeat the five Shardbearers (Godrick, Radahn, Morgott, Rykard, and Malenia) to earn silver trophies.
– Other Bosses: Defeat other notable bosses like Lichdragon Fortissax, Godskin Duo, Fire Giant, Dragonkin Soldier of Nokstella, Regal Ancestor Spirit, Loretta, Knight of the Haligtree, Astel, Naturalborn of the Void, Leonine Misbegotten, Royal Knight Loretta, Elemer of the Briar, Ancestor Spirit, Commander Niall, and Dragonlord Placidusax to earn bronze trophies.

### 6. Endings
– Elden Lord Ending: Unlock this ending by completing the final boss fight and interacting with the statue without saving beforehand. This trophy is automatically unlocked if you complete the normal ending.
– Age of Stars Ending: Follow Randy the Witch’s questline to unlock this ending.
– Lord of Frenzied Flame Ending: This ending can be unlocked similarly to the Age of Stars ending by following specific steps before the final boss fight.

### 7. Additional Tips
– Co-op Summoning: Use co-op summoning to duplicate items like runes, talismans, weapons, and armor. However, spells, ashes of war, and smithing stones cannot be duplicated.
– Explore Optional Areas: Explore optional areas to find hidden secrets and additional resources that can aid in your trophy hunt.

By following these steps and maintaining a strategic approach to your playthrough, you should be able to unlock the platinum trophy in Elden Ring. Remember to save frequently and explore the game’s vast world to ensure you don’t miss any of the required trophies.