/Regen?
Broad Sword, then, though it's pretty much just the same.
"That's because Werner can't do maths." - BunnyAnomaly
"Four hours in, and I was no longer making mistakes, no longer detoggling. I was a machine." - Werner
Videos of Other Stupid Scrapper Tricks
Kinetic Melee for the -DMG/Stuns/Knockdown
Dark Melee for the -to Hit.
Electric Melee for the knockdowns.
All of which avoid redraw issues! \o/
BrandX Future Staff Fighter

The BrandX Collection
Claws and MA work well with it as well.
Broadsword would top the list, depending on how you feel about redraw or having a similar style to your Katanas.
The -toHit in Dark Melee is solid, and on your first pass through a character, you can take Touch of Fear to get another heavy debuff or nearly lock something out completely. Siphon Life does not stack as well as it does with other Secondaries, but it can save you from burning excess Reconstructions.
Kinetic Melee, Martial Arts and Electric Melee have a lot of Knockdowns and stuns to give you time to regenerate or your heals to recharge.
In general, the more mitigation your primary provides, either through self-buffs or debuffs and soft control, the better match it is for /Regen.
11 months of all-nighters, messy feeding sessions, bath fighting and realizing just how good my son's lungs work, and I am still convinced he is the crowning accomplishment in my life. What in the blue HFIL is wrong with me?
What would be a good primary to pair with Regen? I already have 2 50 kats/ so I would rather not use that. Any suggestions would be appreciated.