Ok so I started out Spiral Knight getting the gear I thought looked coolest. I ended up with a Leviathan, Umbra Driver, Chaos Cloak, Chaos Hood, and a Heater Shield. This was about in September to Early December time period. In Mid December I learned how damage types and status resistant worked. I realized I needed to change. So over a time period, I got some new stuff. I got a Dark Thorn Blade(Im working to get it to be 5*) for Beasts and Fiends. I got a Divine Avenger for Constructs and Undeads. I kept my Umbra Driver for Gremlins and Slimes. I got a Royal Jelly helm to protect against Piercing damage. Im still using Chaos Cloak for Elemental damage (Though Im looking to find a better one for elemental). I currently don't have a shadow defense. So I need some help figuring out what I should replace the Chaos set with and What I should get for shadow defense. I also would like to know If it would be significantly helpful to get a shield for these damage types too and If I should get the complete armor/Helmet set for each.
I need help deciding on Shadow Defense and replacing my Chaos Cloak
Since you already have all the recipes for the chaos set and are really considering a set without the negative status resist, id suggest you go grey feather set. This will require you only buy the two 5 star recipes as you already have the rest of the magic line recipes to 4 star. The grey feather set is normal elemental with fire and shock resist. it dosnt have any offensive bonuses but it would be the cheapest option.
Unless your doing shadow lairs id recomend either skelly or fallen or a mix of the two for a shadow set.
I run these three sets as examples
Piercing
skolver coat
dragon helm (elemental & piercing - I run this for a bit of elemental due to the tree men in the wild paths and wolver dens)
barborus thorn shield
Elemental
vog coat
Grey feather cowl
Grey owlite shield
Shadow
Snarbolax coat
Crown of the fallen
Crest of Almire
Just to provide some alternatives to the list above:
Piercing: you can consider Ice Queen Helm as it has the best piercing defense in the game. Since you won't be in a dire need of piercing armor, you could wait until you can get into a party and get the helm
Elemental: For the shield part the Volcanic Plate Shield could be an option. Despite the lack of elemental defense, it works wonder in FSC and UFSC. There're tons of threads comparing VPS and GOS.
Shadow: I personally use exactly this armor set, and it looks pretty good too. However, the curse penalty is a pain in the in the UFSC, as once you get cursed, all 4 of your weapon/item slots would be blocked for 40s. So try to look for an angelic helm with some curse UVs, but it would be quite rare to find (dunno the price but I guess a medium would be cheap). Or else just ignore my comment or just get a snarby helm.
Oh and just start from 2 pieces of armors/shields for each damage type and go from there
I also would like to know If it would be significantly helpful to get a shield for these damage types too
Personally I'd say yes. I think that having a proper shield is more important then having a proper armour/helm. For long time I've been using only one armour set and even now I don't mind wearing "wrong" armour if, for example, I'm levelling one. But I have 5* shield for every damage type and I always equip the one suitable for given level. So far I have Grey Owlite, Dread Skelly and Ironmight Plate shields (plus Scarlet Shield and Swiftstrike Buckler) but I'm working to expand my arsenal of shields. After all, good shield is like a good pudding, you can never have too much of it.
Chaos cloak is actually extremely useful if you play hybrid, due to the universal bonuses. I think the point of going Chaos in the first place is to maximize dmg output and avoid getting hit altogether. You don't need to change your armor, just change your playstyle to compliment your armor.
Start using weapons that use CTR (Divine Avenger was a great choice for your set btw!)...such as a brandish, haze bomb, even a blitz needle (Chaos Cloak makes Blitz Needle really shine!).
Start playing as if you needed to avoid getting hit altogether, and you'll see the difference right away. If you ditch the leviathan you'll have no need to get that close to enemies.
You don't really need a complete set of armor and helm for defense. I am doing quite fine without those. Just focus on weapon related bonus. wolver line for sword, gunslinger line + seerus mask for gun and demo set for bomber. These sets would help you kill monsters much faster. However, shield with correct damage type could make your journey significantly easier, assuming you always use your shield at the right time. I usually get all three defense shields (grey owlite: elemental, barbarous thorn: piercing and crest of almire: shadow). I also have swiftstrike. I use it whenever I feel the clockwork is easy.