I did a playthrough of this mod using only the Necrotic damage weapons, aside from the very start. I got the impression of blood magic way more than necromancy, since I didn't notice anything like summoning the undead. The armors do look like necromancers however.
I find this to be an interesting take on a new class. It's not just a new damage type, but rather it just straight up includes the main damage classes plus Thorium's two new ones. I find this works well given how the main damage types cover almost all styles of weapons already and Necrotic weapons fit within those lines. It's a new take on the pre-existing classes by adding in a life steal and life drain mechanic. I stocked up as much health as possible, reforging all my accessories to JoostMod's Hearty prefix, for 25 extra life per accessory.
I found throwing weapons to be by far the weakest of other Necrotic weapons. I liked how the symphonic weapons had empowerments that built up over time. Between certain weapons of the same tier like the Channeler and Regenerator, I found the former did almost 1/10 of the DPS compared to the latter. That's one of the ways I can find the balance really off between weapons. Out of the aquatic symphonic weapons, I found the Aquatic Strings had by far the greatest DPS to the rest of them. I liked the accessory to make summoning costs the same instead of scaling with minion count, even if it could get a bit powerful.
I made it to the end game and only started dying around that time where's before I made it pretty far with no deaths. The four end game weapons don't cover throwing, radiant, or symphonic weapons or helmet effects. I know Thorium had up to four weapons per class at this stage, but I think given the nature of Necrotic weapons, an exception can be made to include the other three weapon sub classes. Granted I'm not sure what theme the other three would be since the four already in are named after the Four Horsemen of the Apocalypse.