Get them all to get the platinum.

Beat 1-1 world boss Phalanx.

Beat 1-2 boss Tower Knight. Make sure to get the "One Shall Fall" trophy as well - do not kill any archers during the fight.

Beat 1-3 world boss Penetrator. Make sure you also get the Brother-in-Arms trophy - You need to save Biorr before the fight so he can help you.

Beat 1-4 world boss False King.

Beat 2-1 world boss Armoured Spider.

Beat 2-2 world boss Flamelurker.

Beat 2-3 world boss Dragon God. Make sure you also get the Fists of Legend trophy - you need to finish him off using the Hands of God weapon.

Beat 3-1 world boss Fool's Idol. Make sure to get the Not Fooled trophy - you need to kill her without hitting her clones.

Beat 3-2 world boss Maneater.

Beat 3-3 world boss Old Monk.

Beat 4-1 world boss Adjudicator. Make sure you also get the One Shall Stand trophy - killing him without hitting him down. You will want to use arrows.

Beat 4-2 world boss Old Hero.

Beat 4-3 world boss Storm King.

Beat 5-1 world boss Leechmonger.

Beat 5-2 world boss Dirty Colossus.

Beat 5-3 world boss Maiden Astrae. Make sure you also get the May you be unharmed trophy - you can't kill Garl Vinland during the fight. Arrows will be your friend.

For this you will need the Blue Eye Stone. After defeating the Phalanx and talking to both Maiden in Black and the Monumental in the Nexus you will get it. Now you just need to leave a sign (try in front of some boss doors) and wait for someone to summon you.

You need the Black Eye Stone, which you can get by defeating your first Black Phantom in the game (red enemies). Now you can use it to invade other people in order to kill them. Try Prison of Hope on the stairs before the boss Fool's Idol. Or any other location really, good locations are before the boss fights.

During the Tower Knight boss you want to kill just him, not the archers that are shooting from above. It's actually quite easy, just forget the exist and make sure you have a good dodge strategy (load < 50% helps alot). If you miss this one, you need to try again on new game +.

Biorr is locked in the cell in world 1-3 (Inner Ward). First, you will need to defeat 3 bosses on each world to unlock path towards 1-4. By progressing from 1-3 towards 1-4 you will encounter Fat Official enemies. First one will give you the Iron Key Ring. Now teleport back to 1-3 and turn around. On your right through the building are the locked doors. Open them using the key, kill another Fat Official, grab his key, open all cells here. In one of those is Biorr. Talk to him few times. You can now try fighing boss at the end of 1-3 - Pentetrator. Biorr will help and make the fight easy.

0:01 - Finding the Iron Key Ring
1:35 - Free Biorr from the cell using the Iron Key Ring
2:49 - Defeat Penentrator with Biorr's help to unlock both boss trophies

Teleport to 2-2 (The Tunnel City). Go north and take the right tunnel. At the end smash some boxes and now you need to reach the bottom by falling but be careful not to die. When you reach bottom just go through the only tunnel, turn left at the end and reach the shinning corpse. Loot the corpse to get the Hands of God.

Now, Dragon God has few phases. You need to shoot 2 arrows at him. He will lie down afterwards. Equip Hands of God and finish him using that weapon. Be carefull, you can land 2-3 hits before he sets you on fire. Take your time.

0:01 - Hands of God Location
1:33 - Fight with the Dragon God
5:05 - Master's Ring

At the bottom of world 3-1 (Prison of Hope) there will be a shooting statue. It should be on your way as you progress. While it shoots you need to roll/avoid the arrows and reach behind of the statue where you can turn it off. You need to do this before reaching its back via alternative route. 

She is the boss in world 3-1 (Prison of Hope). First you need to kill the minion, which is in the right tower (when your back is facing the big shooting statue just before the boss). Climb up and kill him so he doens't resurrect the boss. When you deplete half of her HP, she will summon clones. You can't hit any of those. The trick is to get close, press R3 to aim and observe if you see the health bar. If yes, DO NOT hit, if you see only the aim icon - hit. Simple as that.

0:01 - Kill the minion just before the boss fight
1:14 - Fool's Idol boss fight

You can find Compound Short Bow after teleport 1-2; top of the second tower when you run through the bridge where red dragon spit fire. Compound Long Bow requires a bit of Strenght and Dexterity, so you might want to use the Short one instead.

Prepare a bow and at least 50 arrows (you can buy them from blacksmith in Nexus). Visit world 4-1, go straight, before the demon in the courtyard go left through the narrow hallway, up the stairs, straight where skeletons are. You will need to roll on the wall, don't go down the stairs. When you do, fall down and you will be in the outer part of the lower area. Follow the path and you will reach the upper part of the boss area with Adjudicator. Use your bow to shoot him in the head, which is also his weak point. Be careful when he uses his tongue. You can't attack him in his belly to make him fall down.

0:01 - Compound Long Bow Location
1:26 - Path to upper Adjudicator boss area
3:50 - Adjudicator boss fight

This is the boss in the world 5-3. When you enter the fight, make sure to go right, not down by any mean. Prepare your bow and at least 100 arrows and start shooting from the ledge. You can just barelly hit her while Garl is stuck down bellow. She will heal, but just continue attacking.

Old one is the boss of world 1-4 (False King). I suggest backing up a save file before the fight. Kill the False King, don't leave the room, kill the Maiden to unlock the trophy. 

Now, restore the backup file, kill the Fake King again. This time don't kill her, instead allow her to put the Old One back to sleep - this will grant her soul which you will need for a spell in a new game +.

When you reach the big statue that shoots arrows in world 3-1 (Prison of Hope), you need to get behind it.

Get the Special Key (at the far end in the tower, which is east when your back is facing big statue with shooting arrows). With this key you can open cell doors to save Freke and unlock A Dash of Sage Trophy. From starting point he is on the right side of the halway which connects from the middle of the stairs when you start descending down. If you reach the hallway that has 2 doors on the right and stairs to go up again you've gone too far.

0:01 - Path to the Special Key from teleport 3-1
3:14 - Path to Freke from the teleport 3-1

Note:
If you completed World 2 (Stonefang Tunel) he will move to 4-2 location no matter if you found him in 2-2. Otherwise you can find him in the huge lava area in 2-2 and talk to him there if he doesn't progress to 4-2.

You will come across Saint Urbain in world 4-2. From that checkpoint, go straight, down the stairs and back inside again. Fall down next to the reaper enemy, kill it. Descend the stairs and turn back, you will see a path inside of the room that is just above where the reaper was. Talk to Patches here, get close to the pit and he will push you inside. Talk to Saint here and try to leave via the opposite door. Beat the Black Phantom and talk to Saint again. He will now move to Nexus when you teleport out of this dungeon. Simply exit through the door here to unlock the trophy.

To get Satsuki to appear you need to have Pure White World tendency in world 4 (Shrine of Storms). He will just just at the entrance here. Talk to him and now you need to find Makoto sword. Again, you need to have Pure White World tendency in world 4. Got to room where Patches pushed you in the pit:

You will come across Patches in world 4-2. From that checkpoint, go straight, down the stairs and back inside again. Fall down next to the reaper enemy, kill it. Descend the stairs and turn back, you will see a path inside of the room that is just above where the reaper was. If you did this quest then you can just descend the stairs across the hole and pick up the Makoto from the ground in the ground floor room. If you didn't do the quest yet, talk to Patches and get close to the pit so he can push you down there.

With Makoto sword go back to 4-1 and talk to Satsuki again. Beware, doesn't matter what you answer, he will still attack you. Kill him.

0:01 - Speak to Satsuki in 4-1 while having Pure White World Tendency in World 4
0:40 - Teleport to 4-2 and loot the corpse in the room Patches shoved you in (also required Pure White World Tendency for the corpse to appear on the floor)
1:40 - Speak with Satsuki again and be prepared, you will have to kill him

To get the Searing Demon Souls you need to beat Flamelurker - boss in world 2-2. With that in your possesion, teleport to world 2-1. Go up the stairs, straight in the building just left of the merchant and down the moving elevator (considering you unlocked this shortcut). Talk to Blacksmith Ed ("Talk" option for a few times until he start repeating the conversation). Now, move away from him and talk to him again. He will now mention Searing Demon Soul and you can give it to him. Do so and you will unlock the trophy, plus you can now create weapons from boss's souls.

0:01 - Long way towards Blacksmith Ed
1:58 - Make sure you killed Flamelurker and got his Searking Demon Soul
2:07 - Talk to Ed and give him the Searing Demon Soul

You need Pure White World tendency in world 5 (Valley of Defilement). Teleport to 5-1 (Depraved Chasm) and follow the route down. You will eventually reach a room with multiple small rats. After that room in the middle of the next path wall is a ladder (appears on when you have pure white tendency, so +3). Climb it and you will reach Istarelle. Be carefull about the ogre enemies, kill them and you can pick up the weapon.

First, you will need to defeat 3 bosses on each world to unlock path towards 1-4 (world 1 - Boletarian Palace, teleport 4). By progressing from 1-3 towards 1-4 you will encounter Fat Official enemies. First one will give you the Iron Key Ring. Now teleport back to 1-3 and turn around. On your right through the building are locked doors. Open them using the key, kill another Fat Official there, grab his key - Bloody Iron Key.

Now teleport to 1-3 again, but this time go straight and enter the small alley just right of the first car you see (the bouncing one with the caged dogs inside). In the alley you can now unlock the door with the Bloody Iron Key. Follow this path until you reach the top of the stairs. 

Equip the full Fat Official set:

Official's Cap (second Fat Official when goind from 1-3 towards 1-4, which is behing the bars. You will reach him via alternative route, just don't go in boss direction, go opposite when you get to that area)
Official's Clothes (World 2-2 - The Tunnel City - Kill one of the Fat Official's there. He is just at the end of the left tunnel straight from the starting point)
Official Gloves (World 2-1 - Smithing Grounds - Kill another Fat Official's there)
Official's Leggings (World 2-1 - Smithing Grounds - Kill yet another Fat Official's there)

Fat Official will lower the stairs. Backstab him and finish him off. Equip something else and talk to Yuria (otherwise she will think you are the enemy) for a few times. Trophy unlocked, Yuria will now move to Nexus next time you teleport there.

0:01 - Find Iron Key Ring starting from 1-3
1:35 - From Iron Key Ring, continue and kill another Fat Official for Official's Hat
3:03 - Use Iron Key Ring to enter Biorr cell area (from 1-3 again) and kill another Fat Official for Bloody Iron Key
3:52 - Collect Official Gloves and Official's Legging from Officials in 2-1 (kill all 3 and loot them, 2 will give you needed equipment)
5:42 - Official's Clothes - From 2-2 just go straigh and left. Kill Fat Official behind the corner
6:23 - Equip full Official Set
6:30 - Make your way towards Yuria from 1-3 again. You can use Bloody Iron Key to open the doors on your way there
7:57 - Make sure you remove Official Set and talk to Yuria so she can move to Nexus

Couple of items you need for this one.

Demonbrandt - This is the sword that is given to you by Old King Doran. First, you need the Mausoleum Key. To get it you either have to kill Ostrava or finish his questline. In this version this is not glitched, so don't worry too much. First encounter with Ostrava is in 1-1, then 1-2, then 1-3 and finally you can find him bellow the Blue Dragon inside the tower. Ostrava should be there on his knees. Talk to him to get the key. The easiest way is to kill him when you first meet him.

Now teleport to 1-1. On top of the left tower there is path you never took since there is that strong knight enemy (if you arrive from the tower via shortut, go straight, if you get there through the stairs it's south). You can use Mausoleum key here to unlock the door. Talk to Old King Doran, keep attacking him until you deplete 25% of his HP and he will grant you the sword.

Note: Killing Old King Doran lower the world tendency by 2 points.

0:01 - World 1-1 - Help Ostrava and kill enemies (you can kill him now to avoid his full questline and get the Mausoleum key)
2:21 - World 1-2 - Talk to Ostrava and get to him through the tunnel
4:10 - World 1-3 - Rescue Ostrava when you open the gate shortcut (if you miss earlier part he will not be here like it was for me, but he will just move to next step)

NOTE - This step is with Biorr, not Ostrava! I made a mistake, just skip this step.
4:32 - World 1-4 - Defeat Blue Dragon with Ostrava. He will give you the key afterwards. If he dies (and he will), just enter the palace and find him on the stairs

6:52 - Teleport to 1-1, open doors with the key, talk to Duran, deplete 25% of his health and grab the Demonbrandt Sword
9:55 - OPTIONAL: Kill Old King Duran to get his set (Ancient King set)

False King’s Soul - Defeat the False King (1-4 world boss)
Soulbrandt  - Defeat the Old King Allant at the end of the game

When you start your new game plus, you need to visit Blacksmith Ed in 2-1 and you need to give him Searing Demon Soul for him to make boss weapons. Now craft the Northern Regalia.

You need all Magic Spells for this trophy.

Demons Souls Remake - All Spells and Miracles Guide

You need all Miracles for this trophy.

Demons Souls Remake - All Spells and Miracles Guide

You need all 30 Rings for this trophy.

Demons Souls Remake - All Rings Location Guide