I used to do Index with Excal Umbra and a Kohm w/ Riven, then DE nerfed. I turned to Rhino, and my Plague Kripath Zaw w/ maiming strike and a slidecrit riven, then DE nerfed. NOW we're onto what I assume MUST be the next nerf - [Titania].

I am 100% convinced that this is the ultimate [Titania] build for Index. I have tried many builds and done enough runs to earn over 100m credits. This one just doesn't ever disappoint.

The playstyle is simple: Run Zenurik focus for the freecast every 60 sec, precast Eclipse before energy spawns and stand on energy spawn. As soon as it pops, Razorwing.
If energize procced, spam Eclipse (and Spellbind on self if you want the status immunity) to 4x [Razorwing Blitz] and annihilate everything
If energize did not proc, rotate to next energy spawn and repeat previous step

This build can pick up 15+ points and still zoom around not giving a sh*t. She's extremely high damage, extremely high mobility, and somehow can generate enough energy to not care about the insane drain of zooming around with 15 points on her. Just make sure you tap energy orbs as you NYOOOM by at mach speed. This build is so fast that I rely entirely on shieldgating without actually HAVING any shield gen. You almost never get hit, so when you do, you just NYOOOM around a corner, get shields, and go back to killing. This is so infrequent that it hardly impacts the speed of each wave.

There are very few changes I would make to this build, but if you want flexibility, you CAN aura forma and swap in Brief Respite for shield gating if you're somehow getting hit frequently. If you intend to just do the first 100-200 pts and reset, you could swap out [Growing Power] for [Enemy Radar] (stacks with [Vigilante Pursuit]) to see enemies even further away and speed up cleartimes slightly. The build now includes a shield gating solution. If you just intend to do shorter Index runs and want a lower APM build, you can refer to the old build below.

That's it. That's the build. Titania absolutely F*CKS in Index and I highly recommend you try her out if you have these mods/arcanes in your arsenal.
I will link the Dex Pixia build here: https://overframe.gg/build/336336/

PS - this build DOES work outside of Index as well. You can swap out Vigilante Pursuit for Preparation for quick capture/exterminate/rescue missions or run Power Drift if you'd like to forego radar altogether. I intentionally left this slot unpolarized so you can run whatever you like here. In order to accommodate the shield gate build while still having room to use the low-APM build if desired, I've moved the dash polarity from Streamline to Vigilante Pursuit. This means you'll either need to add starting energy with archon shards or commit to one build or the other. If you wish to use the shield gate build everywhere, move the dash polarity from exilus slot to a D polarity on Catalyzing shields or V polarity on Precision Intensify (the former allowing 1 more capacity).

For missions where Eclipse does not work (such as the entire last update), I'd recommend running Roar, Xata's Whisper, or the new fan favorite Nourish.

1/14/23 UPDATE: Added shield gating w/ new Catalyzing Shields mod and swapped a few other mods for better power str.

For historical purposes, here is the old build which STILL WORKS so long as you are okay with not having a 1.33s shield gate. In Index, it isnt the end of the world if you die once every 2 hours because you tanked 2 Raptor rawrXD clouds back to back. You just fly back and kill the guy that picked up points. I've never failed a run from this. HOWEVER, I did hours of testing with several new mods and have found a reliable setup that enables shield gating and actually results in higher ability str for Razorwing Blitz. We trade off duration for this significant boost in power, so the build requires more management (in the form of recasting 1 and 3 more frequently, and lining up energy orb pickups with eclipse casts). This actually helps since it means we're resetting our shield gate more frequently. Additionally, it is very helpful to run a kitgun with Augur Pact, Augur Seeker, and Pax Bolt. This will give us better Energy > Shield conversion for gating (which scales LINEARLY with Catalyzing Shields, which makes this build viable outside of Index, where a single Eclipse cast doesn't 100% recharge your shields).