From Guild Wars 2 Wiki
Blademaster's Core is a part of the HOPE IV: The Catalyst collection.“
— In-game description
- Given after completing Defeat Blademaster Diarmid (80) [Group Event]
- Once the Incomplete Catalytic Converter has been unlocked, this item can be obtained on any character, the Converter does not need to be in your character's inventory
- You may only earn this item by killing this commander during the assault on the Blighting Towers. Other appearances before or after will not give a Core.
- To save time, you can participate in all three Blighting Towers boss events during a single Dragon's Stand instance, and you will receive all three cores which are needed for the Catalytic Converter. Only attacking the boss during these events will not give credit for event participation, you must kill some mobs as well.
- The Core is given once all three commanders are slain.
- See Incomplete Catalytic Converter#Notes for more information.