I wasn't sure where to post this as it's technically a druid ability but more about a build that involves 0 druid levels.
I've been playing a tempest ranger/monk life that's high wisdom and dexterity and using the flame blades from the druid past life. I've noticed a lack of talk about these weapons so I figured I'd put in what I've discovered by level 9.
-The past life feat version of the scimitars do in fact use character level as caster level, as expected.
-For some reason it's counting me as caster level 10 at level 9 though, giving the level 10 version of the blades.
* This seems to have been a one time bug, every time I cast them now they give the proper caster level.
-The weapons deal pure fire damage in a way similar to the Flaming effect on weapons, and as such ignore material DR(such as bludgeoning, slashing, yet to test if they bypass silver or good DR)
-That being said, they are affected by standard fire resistances and immunities.
-I have noticed that they do *not* take damage from oozes, nor do they split them, due to being pure fire and not slashing weapons.
-They are affected by *most* effects that apply to two-weapon fighting, such as the feats and tempest core abilities. Even dex-to-damage seems to apply to them!
-That being said, the one thing that I found the most frustrating was that there is a lack of ability to increase their threat range. Due to not being slashing weapons,(despite being scimitars) they are *not* affected by the improved critical: Slashing feat, nor are they affected by Fire Lore items. As of now I've been unable to find any way to improve their threat range.
All in all I've found them to be a really useful item while leveling, and dex to damage is going to be wonderful, so I definitely think they are worth a feat slot if you have the druid past life and can spare a feat. I just wish that there was some way to increase the threat range.
If anyone has anything to add to this by all means do, I'd just like to help out anyone considering using them as a build especially since U19 seems to have made them more viable with the ability to add dex to their damage instead of wisdom.