Okay so I have one party member who learned of advanced classes and all these paths he could take, originally from vermin lord, then he asked a question I'm having troubles answering. And that's about shadow manipulation. Or more accurately forging. Is there a spell line or set that could achieve this? Like making swords, shields, or even simple armors out of darkness?

Nothing specifically like that, but Warlock has some features that fit thematically. And you can reflavor spells.

Warlock features pact of blade to make a weapon. There is an invocation called armor of shadows (but it is just the ability to cast mage armor).

Mage armor, shield, misty step, darkness and shadow blade can all be made to fit. And more if you are creative.

There is also a shadow magic sorcerer.

It sounds like he is asking about abilities and classes from 3rd Edition, so that might by why you are having trouble. You probably won't find much of those in the regular rules, though like DxJxC said, just find a thematically similar spell, and reflavor it.

You could also just flavor their spellcasting as "pulling the shadows from the area, coalescing them and weaving them into the magic."