Parry is the tight-timing, high-reward option; dodge is the forgiving one. Chroma is the merchant currency; weapons upgrade on a separate material. Lumina is what a mastered Picto turns into once you've won four fights with it equipped.
Parry blocks an attack entirely and hands you back AP, but you only get one narrow window to press it; dodge is far more forgiving and lets you tap through a whole combo, at the cost of never rewarding you for it. Chroma is the currency you spend at merchants and at Camp — it doesn't touch your weapons. Lumina is the passive effect a Picto turns into once you've won four battles with it equipped, and it's the whole reason the Pictos menu looks more complicated than it needs to.
Both defensive options key off the same instant — right before the enemy's attack actually connects, not when the animation starts. That's the part beginners get wrong: waiting for the hit to look imminent is already too late, and swinging early whiffs it too.
Where they differ is what happens if you're off. Dodge is lenient — its animation is quick enough that you can tap it several times through a multi-hit combo, and even a slightly early or late press tends to clear the hit. It costs you nothing but also gives you nothing beyond staying alive. Parry has the same instant but a much tighter margin, and missing it means eating the attack in full, with no partial credit. Land it, though, and you get AP back — the resource that pays for skills — and if you parry every single hit of a multi-hit attack, it triggers an automatic Counter that blocks the whole thing and slams the attacker for real damage. Dodge is the safe choice while you're still reading an enemy's patterns; parry is where the AP economy and the damage actually come from once you know them.
There's a third option layered on top that the tutorial mentions once and never again: when an enemy attack makes the screen flash grey and slow down, that's a Gradient Attack, and neither dodge, jump, nor a normal parry stops it — you need a Gradient Counter, input on the dash button instead of the parry button. The slow-motion is cosmetic and actively throws off your timing if you follow it; treat the grey flash exactly like a normal parry window and press right before contact, not during the slow-down. Some enemies mix Gradient Attacks into an otherwise ordinary combo, so the read you need is "which input does this specific hit want," not just "when."
Chroma is the money of the game — what merchants take for weapons, Tints, and Music Records, and what you spend at Camp to upgrade Expedition Resources. If you're hoarding it wondering what it's "really" for, that's it: it's currency, and it drains the way currency does.
What it is not for is leveling up the weapon you're already carrying. That runs on a separate material called Chroma Catalyst, dropped by enemies and bosses and found in chests, with tougher tiers (Polished, then Resplendent) needed for higher levels. From Act 1 you upgrade weapons through the Curator; from Act 2 onward you can do it at any Expedition Flag. The other way to push a weapon's level is finding a duplicate of it — a second copy of the same weapon raises its level on its own, no Catalyst spent. Full stats and where every weapon in the game ranks are in the weapons database.
A Picto is the item itself — equip it on a character and you get both a passive effect and a stat bonus, but only three Picto slots exist per character, and only one character can wear any given Picto at a time. Full effects and where to find each one are in the Pictos database.
Mastering a Picto is what unlocks its Lumina: win four battles with that Picto equipped, tracked against the Picto itself rather than the character wearing it, so two wins on one character and two on another still add up to a mastered Picto. Once mastered, every character can equip that effect as a Lumina — but a Lumina only carries the passive, never the stat bonus, and it costs Lumina Points to slot in rather than taking up one of the three Picto slots. That's the trade: Pictos are scarce and personal, Luminas are shared and cheap in slots but metered by points. Passive effects that pair well with a build often live behind a skill choice too — worth checking against the skills database before deciding which Luminas are worth the points.
By default, a character's total Lumina Points equal their level — a level 20 character has 20 points to spend across every Lumina they've unlocked, and pricier Luminas can cost up into the double digits, so hitting max level doesn't mean you can run all of them at once. The only way to raise the total beyond your level is the Colour of Lumina, a material the Curator at Camp converts into a permanent extra point per copy spent — permanent, and not refundable. Colours of Lumina turn up as loot, boss drops, and quest rewards, and later areas drop them in bulk once you're strong enough to farm the tougher fights there.
Put together, the loop is: fight with a Picto until it masters, spend Lumina Points to wear its effect on whoever needs it, and raise that point total either by leveling up normally or by feeding Colours of Lumina to the Curator. None of the three systems talk to Chroma at all — that stays in its own lane, buying gear and camp upgrades while the combat and build systems run on wins and points instead.