mid-game dual blades build?

[sparda]

I got bored of the Insect Glaive

[Zero Precision]

All the gear I have listed is High Rank.*

Weapon(s):
Arcanaria III (Kulu Tree) or Sin (Odo Tree)

Armour:
Strategist Spectacles A
Rathalos Mail B
Odogaron Vambraces A
Odogaron Coil B
Rathalos Greaves A

Charm:
Attack Charm III

Slap on the free attack jewel you get for reaching high rank to reach attack 4 (+5 affinity) and now you have an 100 affinity build (affinity is the chance to deal critical damage).

Just wound and focus monster's weak spots (typically the head or tail) by using the clutch claw and deal critical damage.

Both weapons can be boosted by Non elemental boost too, as long as you keep their element dormant.

If you find the DB aren't for you and you want to go back to using IG, then you can still use the build with the Insect Glaive: Vice (Odo Tree).
its element is dormant, so non element boost should work for it too.

[Visc3r4l]

DB's are heavily element based weapons, and I'm not sure what you mean by mid game. Are you in iceborne? Or still base MHW? In base game, you can easily get by with defender, or if you don't like that, pretty much anything works (azure starlord set is good, its from an event). If you made it to iceborne, I would go for tigrex armor early and probably tigrex chainblades or the odogaron db's for dealing with dragons later. Then I would go for velkhana's set for critical element, and then transition to silver rathalos , then fatalis. As DB's are reliant on element for good dps, it is heavily based on the monster what you go with. Good picks before alatreon are frostfang barioth db's for alatreon and things weak to ice, furious rajang for thunder, and ebony odogaron db for dragons. FYI beating alatreon and fatalis without grinding the hell out of guiding lands for augments and high tier charms is gonna be rough. I would at least beat ruiner nergigante (MR 100) before moving on to alatreon, but up to you. Then I switched to alatreon db's for fatalis. Kulve tarroth weapons are arguably better against fatalis, but I didn't worry about kulve. For fatalis, I used a silver rathalos set with arch tempered namielle gloves.