A bit too early to say for sure but theres a few things it could be.
the new weapons of the 4 horsemen
new starting weapons (but where is the 1-handers?)
new spec hint
generic dk npc weapons
Let’s assume they are just placeholders for now and that the freezing blade and Burning blade are possibly meant to be the 1-handers together… tho would that mean frost would also gain fire effects?
There is something else i just remembered however, originally the death knight was actually able to rune their sword with fire, i believe it was called lichbane, it ended up inferior to razorice in the end as it’s effect was almost identical with bonus damage to undead.
There is one final possibility in all of this however, and that is that they are going to perform a complete rework of the death knight, potentially expunging dual wield and centring the entire class around 2-handers.
I hope we do not get a new spec. Aside from fire having nothing to do with the dk class fantasy (Bolvar is a massive one-off special snowflake and should stay that way) it would also mean that there would be yet another spec to balance AND it would mean that this spec has no artifact weapons from Legion.
Similar to green fire for warlocks? I get you.
But you know all of the other specs will then start sniping at each other because they didn’t get anything.
I think they just start with this. More will coming. It’s like “let’s throw this and see what happen. If people like it, we do more visual upgrade for characters” = profit.
Death knights are made to kill things, it does not matter how they do it as long as they do and as just about anything can be used to kill this also means that just about anything would be thematic for a death knight.
Death Knights and the Scourge were always portrayed as the icy harbingers of death from the cold north, commanded by the frozen throne. Ice, death and plague were their main theme. Fire would be something completely new and non-thematic.
actually the ice only came into major play when they were in northrend, hell the only units the scourge had with any frost effect was the Lich, nerubian towers and their necroplis even then. They actually didn’t use frost all that much considering…
It is to my understanding that like any force, they adapt to their situation, if there is an overabundance of fire in an area then they will use that but if there is alot of water then they will use that instead.
Remember that the scourge actually hosts a very diverse set of people and backgrounds, they even use corrupted “unholy” light as a weapon in some instances, they even had emberwyrms BEFORE bolvar was lich king.