Remnant: From the Ashes

Explanation
You will receive a +5 boss weapon (Riven +5) as the reward for handing over the beast heart (from Ixillis XV) to the undying king. This won't cause the achievement to unlock however. Now, you need to upgrade any boss weapon to +1, unlocking the achievement. As for crafting boss weapons... Upon killing either "Singe" or "The Ent" (depends on your world generation) you will receive a crafting material which can be used along with ~600 scrap, ~7 Lumenite Crystals and the boss material.

Simple Breakdown
1. Kill Ixillis XV to receive beast heart
2. Give heart to Undying King to receive Riven +5
3. Craft any boss weapon using:
~600 Scrap
~7 Lumenite Crystals
1 Boss material (First available are from "Singed" or "The Ent")
4. Upgrade a boss weapon to +1

Farming Lumenite Crystals
Because each person's world is unique, I am unable to point you to a specific checkpoint to farm at. However, I can give you an important tip from my own experience.

Pay attention to the spawns near your checkpoints! If there is a special enemy very close by, then you can kill that special enemy and then reset the spawns to farm crystals. Personally, at my "Pan Flautist" checkpoint in Yaesha, I was lucky enough to have a special enemy spawn right beside my checkpoint. Close enough that depending on how close the spawn was (the spawn slightly changes each time you reset the enemies at the crystal, but the enemy types will stay the same), he could be within aggro range without me even having to move. It should also be noted that at least for "Pan Flautist" the enemy spawns did not go away even after clearing the area's boss. I'm not sure if this is the case for all areas however, so consider doing some farming before killing the boss.

Good Luck!

In this video guide I will show you how to craft a weapon using material from a defeated world boss then upgrade it to level five. Now typically the first run on a campaign roll world boss will be Singe. Who looks like a tree root dragon. If you want to know more about him I also have a video here.


Once you defeat Singe you will get a Blazing Heart in your inventory items under the materials tab. Once you get that head back to Ward 13 and talk to the sassy mod lady. You will then be able to craft it from her.

After that head to the merchant guy who sells the guns and upgrades them. Simply upgrade it as far as you can. Now chances are you did this right away and can't get it all the way. You will need plenty of iron, lumenite crystals, and forged iron. Forged iron will be dropped later on by the enemies so don't worry there. Once you get enough of it you will be able to upgrade it to level five for the achievement.

Just on a side note there will be plenty of other world bosses who drop the items to craft more in case your campaign is different. As well as some mini bosses as well. Which should count since the game is glitchy enough. If not let me know and I will remove this little add-on.