Make fusion weapons. Yes, Yu-Gi-Oh style.
There should be a option to combine two 5 star weapons of any weapon line(as long its Gun+Gun and sword+Sword--- eg. Blitz+Grim Rep) and make a powerful weapon with half shadow and half piercing damage (with some Monster Dmg UVs thrown in for good measure). Looks awesome. Animation is ULTRA COOL.
Downside, acquiring its recipe. The recipe costs 100k crowns. And the only way to get it is doing an Arcade gate from Depth 0-29 on Elite using no sparks. If u die twice, well, keep using your Blitz and Grim Repeater. And you can do the recipe run only once per day. And the Fusion Recipes are not guaranteed.
Crafting Guide: To craft it, you need 9 Elite orbs, 100k crowns(yes, again) and 1000 Energy.
Need double amount of Radiants to heat it up, and Forge Prize Box chances are increased by 3 times.
That's what we need. Add in a few prize boxes that have 0.001% chance of one random Fusion.
You can't make Fusion weapons of 'special' weapons like Tortoguns and Overcharged Mixer.
Some concepts:
Blitz+Grim: This modernized, superpowered Autogun will shred anything to pieces, as long it's not Vog himself. Downside, increased Reload time.
DA+GF: The ultimate bane of Constructs. Curse gauranteed on Charge attack but charge is super OP.
Final Flourish+Acheron: The speed of the Final Flourish combined with Shadow damage from Acheron. A nice new weapon for speed-lovers.
How's my idea. Comment +1 and improvements if you like it.
That's all for now,
Snarby
This would require a lot of extra work not to mention that resists from monsters actually drop damage more than effectiveness boosts it. Simply put split damage weapons that aren't half normal actually have lower DPS than pure damage weapons or split with normal weapons. So this would ruin your autogun combo.
It would also ruin your DA/GF unless you plan on giving it an unprecedented 3 damage types and even then the effectiveness against undead and gremlins would severely drop. It would also be weak against fiend and beast.
If you are suggesting a shadow/pierce sword it too would suffer like the others. If you are suggesting a sword that attacks like a flourish or is as fast as a flourish but is as powerful a the Shadow/Normal Acheron it would be totally broken and would ruin PVP.
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I don't think that there should be weapon fusions but I would like to see other damage types in weapon families that are limited to one or two damage types.
Example: A Calibur that deals pure pierce damage, a Flourish that deals pure shadow damage, etc.