After obtaining your first boss soul in Dark Souls Remastered, you might be tempted to consume it immediately for the extra souls. While these powerful souls will dramatically increase your number of souls, you should, however, use them for their intended purpose i.e. crafting Boss Weapons.
To create these boss weapons, upgrade a pre-requisite weapon type for the boss weapon to +10, and then ascend it using the boss soul at the Giant Blacksmith. Each boss soul has specific weapon types that you can use.
The entire process confused me initially, but I’ll explain the usage of boss souls in Dark Souls Remastered to make it easy for you.
Upgrade your weapon to +5
Before we can make a boss weapon make sure to check the required weapon type for the Boss Soul in your possession. You can check the Dark Souls Remastered Boss Weapon Wiki for these requirements.
After you have chosen which weapon you’d like to create, you need to upgrade it to the +5 level. This can be done at any Blacksmith in the game by selecting the Reinforce Weapon option. To do this, you’ll need a total of 9 Titanite Shards.
You can either buy these shards or farm them. Blacksmith Andre sells them for 800 souls each. For farming shards, kill the Balder Knights in the church near Blacksmith Andre.
The easiest way to get to that location is to take the elevator shortcut from the Firelink Shrine to the church. Fortunately, these shards are easy to obtain. Once your weapon sits at +5, move on to the next step.
Upgrade your weapon to +10
Upgrading your weapon to +6 requires a couple more steps than it took to get to +5, but it’s a pretty simple process:
Obtain the large ember
When I upgraded my first weapon to +5, I found that the game wouldn’t let me upgrade to +6. This is because I hadn’t given the Large Ember to Andre yet.
You need to venture to the kitchen in the Depths to obtain this ember. There is a chest that contains the ember near the first butcher you encounter.
Ascend the weapon past +5
Once the Large Ember is in your inventory, you must give it to Blacksmith Andre. You will notice that the weapon still doesn’t appear on the Reinforce equipment screen.
To fix this, select the Modify Equipment option, which allows you to upgrade it to +6. This will ascend your weapon, and now you can use the Reinforce Equipment option to upgrade it to +10.
Farm for some shards
For the next set of upgrades, you’ll need 8 Large Titanite Shards. There are a few ways to get these shards, but both require some farming.
The first way is to buy them from Crestfallen Merchant in Sen’s Fortress for 4000 souls each or Giant Blacksmith in Anor Londo for 3800 souls each.
The second way is to farm them from the Berenike Knight. They have a high chance of dropping the shards. This enemy is found on the rooftops of Sen’s Fortress and is close to the bonfire for quick respawning.
Upgrading the weapon further
With the shards in hand, it’s time to upgrade your weapon to the appropriate level i.e. up to +10.
You will also need many souls to fully upgrade the weapon, so consume some souls you’ve picked up along the way. Other boss souls you don’t plan on using are also great to consume, just make sure you keep the ones you want.
Ascend to a boss weapon
Now it’s finally time for the easiest step – ascending to the boss weapon. This is the part where you turn your base weapon into the powerful boss weapon.
To do this, simply visit the Giant Blacksmith in Anor Londo. Go to the Modify option, move to the second tab on the right, and you should see your weapon in the list. Your weapon can be ascended for the price of 5,000 souls plus the required boss soul.
Upgrade your boss weapon
With your new boss weapon finally complete, it’s time to upgrade it! The way you upgrade this weapon is by using 10 Demon Titanite. This type of titanite is more challenging to get than the previous two, but there are some excellent ways to get some.
The best way to get a large amount is by farming the Titanite Demon in Lost Izalith. The Titanite Demon in Anor Londo will give you two titanites, but he doesn’t respawn.
The one in Lost Izalith respawns, and each kill will net you 2 Demon Titanite. These enemies are harder to defeat, so be careful.
Giving Dung Pies or Prism Stones to Snuggly will net you 1 Demon Titanite. Two can also be found inside a room with 3 Silver Knights in Anor Londo.
With Demon Titanites in your pocket, take them to the Blacksmith and use the Reinforce Equipment option to upgrade the weapon to a maximum of +5. Boss weapons do not go beyond this level.
You can always consume Boss souls
If you decide that none of the boss weapons appeal to you, you could always use them to increase your soul count. The number of souls these give you ranges from 1,200 souls to 20,000.
Consuming several of these at once will give you thousands of souls you can use to level up and sometimes provide more benefits than boss weapons.
This is the best option if you never plan to use any boss weapons. I find myself consuming them more often than not. The boost in level can help you progress even faster and requires much less time than farming for a bunch of titanite.
Boss Souls are a straightforward aspect of Dark Souls: you consume them or use them to create weapons. Consuming them is the easiest path possible, while creating boss weapons does have a bunch of loops you have to jump through. Do as you see fit!