Dragon Flame Tongue: ???
Perfect Silksword: ???
Staff of Sar-Aggreth: ???

Random spawns. No other way to acquire them atm afaik. You can use the Inferno campaign 4th scenario as my colleague has mentioned to get all three. I;m sure some new way to get them will be introduced in teh patch.

Just at the start of the 4th scenario in the Inferno campaign if you move to the left you will find a stack of fire elementals guarding an artifact. This artifact can be any random item in the game INCLUDING dynasty weapons. It will spawn something different every time you load the game or restart the map. Being so close to the starting point of the scenario (literally you can get there in the 1st turn) it;s a great way to get missing weapons albeit time consuming. It is afaik the only way to get the 3 weapons above w/o using exploits.

Thunder Staff: Orc campaign / map 2 / "Blood" quest - "Might is Right" (also bugged)
Sword of Whistlebone: Orc campaign / map 2 / "Tear" quest - "Time for New Ways"
Malathua’s Cleaver: Orc campaign / map 2 / Main quest - "Wild Card" L.E. (also bugged)

Very handy thread, grats!