Tbh, this might as well be a new job at this point. Complete overhauls of all the animations, VFX, and even some sound effects. Herald of the Dark was something that started out as a Gaia-based mod (real surprise there, huh) and quickly became something new. Aside from Hand of the Master, everything else in the Weapons folder was built for Textools as I was relatively new to Penumbra at the time. I plan to roll out a version for Penumbra in the near future.
If any textures are broken from the 6.5 changes, the fix should be here. https://ko-fi.com/s/46c880720b
If anything else is busted, DM me on ko-fi or on Twitter.