Quality build, onikiri and ubadachi are my favorite and highest win rate. My combo is L1,L1 then once they recover pause for a split second especially if they are parry spamming then finish off with the L2. Pausing for that split second before the L2 also catches them in a roll where you will follow and track them after they initiate roll.
I've started to get into the Brigand twindaggers with Witch's locks as a sidearm.
I also use two shields, Eastern and Llewellyn for a bit safer backstabs and the occasional parry of course. They look similar so if my opponent aren't looking at what I am doing she may walk right into a parry on accident!
I love the synergy between the daggers and the whip as the whip is a defensive weapon that wants to keep the range while the daggers are offensive and requires you to keep up the pressure at close range. The mix is both fun and useful!
What draws me to this build is essentially quickstep. It is the most interesting weapon art in the game in my opinion. But also the challenge of using the daggers themselves in addition to looking like a true diva having them equipped!
The damage is real my friends, only problem is applying it... ;-)