"The brandish charge is a line that does damage, the levi charge can protect you from groups of enemies(or at least it looks like it)"
Brandish and Levi both protect you from groups of enemies. The difference is that Levi pushes enemies in unpredictable directions where they can gnaw on your teammates, while Brandish gives you perfect control over where you push back enemies.
Both do area of effect, the difference is in the area itself.
I know that the damage is more, but I didn't think that it would be almost over 100 more damage(didn't have a lot of time when i made the post)
Acheron would get a bit more damage, to fix that issue
The brandish charge is a line that does damage, the levi charge can protect you from groups of enemies(or at least it looks like it)
The "retrodes can release..." part is because Draycos said that you can insta shield cancel.
Leviathan gives you the free recipes, getting some of the fire/ice/shock materials can be a bit of a problem.(you get the sun silver from missions). I would say that both have the same difficulty to get, leviathan might be a bit easier.
Let's compare the "disadvantages"(i'm not using the current damage values of the line, let's say that they were fixed for this example)
Sk has 3 different enemy groups(i know there are around 6 in total) in most of the clockwork levels(i'm talking about the ones with the gear icon or arenas)
Beast/Slime
Elemental isn't too useful here, shadow works but you will probably have some more hits on the silkwings
Construct/Gremlin
Elemental:
Construct means gremlins, they can be very annoying(some of the most annyoing enemies for me and probably some other players), having to hit them 5 instead of 3 times makes a big difference.
Shadow:
very useful here, silkwings are rare in construct levels, so no big problem here
Fiend/Undead
Elemental:
Perfect here since you will deal more damage to undeads
Shadow:
Shadow had some advantages in the other level, but the less damage is noticeable here.
So, getting a acheron for the first sword might be a good idea, but it will make the fiend/undead levels harder and be less useful for vana(not sure if this is a problem with the new sk battlesprite update, but back then you crafted one sword and had that for the longest time.)