Confusion about demonic weapons

[Raven]

Some of the descriptions are a little confusing, I initially thought all demonic weapons were really horrible...but then after a second playthrough it kinda dawns on me after seeing some other effects that had similar wording... when it says:

"(Passive) Skills(Weapon) gain the following effects: Vulnerable(2) for 2 turns" I originally thought it meant the WIELDER gets the vulnerable, but does it actually mean it INFLICTS vulnerable on the target with weapon skills? If so, does that mean the only draw back to the demonic weapons is the whispers effect they all universally have (plus I guess whatever random story plots that arises from using said weapon I guess that might happen from using them)?

[Kil0]

BP reduction per swing or something too. They arent the best but they are better than most epics. Except the staff, it in fact is the best staff.

[Blood Flowers]

Yes, the only drawback to the demonic weapons is the whispers effect that causes you to lose 2-5 BP on that character at the end of each turn. Surprisingly a pretty substantial debuff if you don't have some significant way of replenishing BP since brave actions are incredibly powerful.