The Invisibles are reminiscent of Darksides, possessing black skin, a similar muscular frame, and a heart-shaped hole in their torsos, but are smaller and more embellished. They have sharp purple and blue horns that form the outline of a curled heart similar to the ones found in the Kingdom Hearts games' logos. They also have small blue bat-like wings on their back, gold-tipped feathered wings on their forearms, and bluish-purple fireballs under their feet, presumably assisting them in their fast movements and tying into their dark fire attack. Their long tails appear scaly, and end in a sharp, crescent-shaped blade.
Unlike many Heartless, which tend to attack with natural weapons like claws or magic-based powers, the Invisible bears a scalloped, blue-bladed sword, which appears blunt, but can unleash powerful physical blows. In Kingdom Hearts and Kingdom Hearts 358/2 Days, the kanji for "Hard Core" (硬核, Kou Kaku?) are written on the hilt of its blade.
The Heartless's name references its ability to disappear when using its "Ring of Fire" curse attack.
The Invisible fires dark energy every now and then, and uses its sword to slash at their target. One of its special attacks includes slamming its sword in the ground, while the main body turns into a ring of dark fire surrounding their target. The ring of dark fire appears to circle the one closest to the Invisible. Once the time is up, the curse explodes, dealing large damage to any member of the party. This can be avoided by jumping, using Superglide, or using Dodge Roll. Like Angel Stars, they have a high rate of dropping a Gale once defeated.
In Kingdom Hearts 358/2 Days, the Invisible has much more health and strength. It can still perform its basic slash attack, but is given an "improved" arsenal of abilities from its Kingdom Hearts version. Its "Ring of Fire" attack is upgraded to cause its weapon to fly at their target up to five times while the beast is invisible, before surrounding Roxas with the ring and striking down with a long-range shockwave as a result. Striking the Invisible before it sends the shock waves will momentarily stun it. It will fire a consecutive string of energy spheres, dealing a high amount of damage and possibly lowering Roxas's Defense to Lv. 1.
Invisibles are a difficult type of Heartless to defeat due to their high hp and strength; they almost always appear in groups and thus can be a huge problem if the player gets overwhelmed. Fights with Invisibles can be made easier through the use of Thunder, Gravity, and Aero magic. Once an Invisible uses its "Ring of Fire" attack the player should time their jump right to avoid the attack, since Dodge Rolling requires more strict if not impossible timing to avoid it; this gives the player to attack the Invisible and ultimately defeat it.
Kingdom Hearts 358/2 Days
It is recommended to equip gear with proficiency in aerial combos, as most of the combat with an Invisible takes place in the air. Watch for when it begins its attacks, and either air slide or return to the ground to block according to the situation. When it vanishes and flies its sword around the area, get ready to glide and make sharp turns when the sword charges.
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