So, I need to gear myself properly.
So, I need to arm myself for runs in Tier 3 solo, but I feel like I don't have tons of useful gears going on.
> Dark Thorn (Intended to turn into a Barbarous Thorn)
> Divine Avenger (My only 5-Star weapon)
> Blackhawk (Wondering if I should upgrade it into Sentenza or an Obsidian Carbine)
> Full Snarbolax Armor (Cap, Armor and Shield)
> Swiftstrike Shield (Must be suicidal for Tier 3, I guess, but goes well with the Snarbolax Rapier above)
As you've seen, my game wanders between swords and guns. I got a Calibur and two Blasters waiting for upgrades as well. Any hints, people?

I (and many other players I know) think that Obsidian Carbine's general poisoning is more useful than Sentenza's gremlin-specific bonus. But I'm not a big fan of antiguas in general. Their damage is mediocre, they require too much clicking, and they're boring. If you want a shadow gun, consider Winter Grave, Umbra Driver, or maybe Grim Repeater. Some players like the blasters; I find them boring and decent-but-not-great in power.
Your swords look good. Barbarous Thorn Blade and Divine Avenger are both good and fun. Don't bother upgrading your Calibur. Consider a brandish such as Acheron.
Your armor is great. Lots of players use Swiftstrike Buckler in Tier 3, because of its awesome offensive bonus. But you must be able to dodge well. If you can't, then consider getting Barbarous Thorn Shield. It still gives a nice bonus to your swords, and it has enough health to survive Tier 3 if you can dodge a little. If you need an even stronger shield than that, then get Grey Owlite Shield (for fire and shock levels) and Dread Skelly Shield (for freeze and poison levels).
By the way, I have a sword guide and an armor guide that you might find useful. Possibly you are already beyond the lessons that they teach.
I just went with what I was seeing around the Wiki. I had strong interest on the Snarbolax set, so I went with it.
I'm seeing your armor guide at this moment, and I sure hit it right with the Snarbolax Armor set. I'm thinking on making a Sacred Falcon Hazard Armor for Slime hunting, thanks to your guide.

I'm glad that you found the armor guide somewhat useful. I would not recommend Hazard armor, because I would never get armor specialized to slimes, but if that makes you happy, go for it.
Hm, I already got the Pathfinder Armor recipes. I intended to use the armor for Royal Jelly and its Shadow Lair counterpart.
BIG HINT: COMBUSTER