Crystal Assassin Hood
5% increased critical strike chance 10% reduced mana cost
2Dropped by
Set bonus
The bonus applies while the helmet, chestpiece and leggings are all worn together.
how you get the set
There is no recipe and no ore to mine for this one. Queen Slime hands over set pieces every time she dies, and in Expert and Master she gives up more per kill, so a couple of repeat fights finish the whole thing. That makes it the obvious answer for anyone who has just reached Hardmode and does not want to spend an evening hunting ore veins.
the dash is the real prize
The full set lets you dash by double tapping left or right. In Classic that is one of only two dashes available before Plantera, and it holds up long past that point. It covers more ground than the Shield of Cthulhu, and with a Cobalt Shield equipped it does not stop when you clip an enemy, which matters against Plantera and Skeletron Prime where a bad bump used to strand you mid-arena. The trade is that ramming something no longer grants invincibility frames, so charging through a crowd is riskier than it looks.
who it suits
The bonuses ignore class entirely: flat damage, flat critical strike chance, and a little quality of life for melee, ranged and magic all at once. Nothing about it pushes you toward one weapon type, which suits anyone still switching between them. It also sits well with placed tools such as the Queen Spider Staff, the Clinger Staff and the Nimbus Rod, since the generic boost applies to them without costing anything on your main weapon.
when to take it off
In Expert the built-in dash frees up whatever accessory slot the Shield of Cthulhu was holding, which for some builds is worth more than the armor itself. Once Tabi or Master Ninja Gear arrives, the dash stops being a reason to keep it on, and any specialized set from Chlorophyte onward will out-damage it for a committed class. Until then it competes with the ore armor of the same stage without asking for any mining.
trivia
The curved horns on the hood are shaped like a kabuto, and that reads as deliberate. This is the Hardmode reply to Ninja armor, which comes off King Slime, the smaller version of the boss that drops this one. It is also the last armor in the game given to you directly by an enemy rather than crafted at a bench.