this mod is in a mix of mods that add weapons alongside better combat (epic knights, simple swords, and this one, etc) one thing I've noticed is the odd behavior with the translucent double greatsword.

after looking around I found that the default attribute set was set to a mace for some reason. Im not sure if you were aware of the options but there IS an option for a twin-blade

all I did was modify the attribute of "better-combat:mace" to "better-combat:twin_blade"
not sure if this is in older versions though but is in 19.2

Oh, and in case you are not aware of this neat thing ill share it with you: if you look in better combats config, you will find a fallback_compatablity file. this contains a rudimentary detection system for assigning attributes with weapons that may not have integrated support for the mod; "Why bring this up?" you may ask, well in it it also contains every possible built-in weapon handling type provided in the mod (no custom ones but the ones provided). In making compat for things like this id find it convenient as it serves as a "catalog" of the attributes I can assign a weapon to if needed

Hope this helps and this is a great looking mod btw