|Spoiler Alert: This page contains spoilers. Read at your own risk.|
Parade (仮装行列) (パレード) is originally an illusion magic that writes coordinates into a false body that is a superficial duplicate that can't be differentiated with the caster.
Parade is magic that creates a phantom in one's position around that area in order to slip through enemy's magic.
Parade can also be used to hide from security cameras.
Kudou Retsu learned by focusing on creating a body clone, his magic, 'Parade', focuses on changing the image of the user.
In Lina's case, her clone's appearance is changed into an image of a golden eyed woman with pink, wild hair, while wearing a mask. This magic is helpful during Lina's fights since all of her opponents' attacks couldn't work on the clone, causing them to have difficulties in fighting her.
In order to break through 'Parade', it's necessary to either locate the body between the time when the old illusion breaks down and a new illusion is created or by disregarding the five senses, one can find the coordinates of the body directly in the dimension of information. Only Elemental Sight wielders are capable of doing the latter. 
While both Minoru’s and Lina’s Parade had the same effect, masking information about the body, the specific processes they used to achieve this effect differed widely.
Since Kudou Ken was a more advanced user of Parade, Retsu had continued to improve the magic sequence to win against his younger brother in skill. This caused the variations in Parade.
“Parade” of Kudou and Lina families were the same in terms of editing and processing copied Eidos and overlaying with original Eidos to disguise it. However, there was a process of turning a copy of the edited and processed Eidos into an artificial Spiritual Being (artificially created independent information body), which was added to Kudou family spell. As a result, the caster is able to perform activities such as maintaining, restoring, changing and moving "Parade Spiritual Being" after the magic was activated.
It is possible to attract the enemy’s attention to the disguised information body copy with such a structure of Magic Sequence. And further mislead the enemy by distancing the copy from the original. The copy and the original would be located in different places, so if you destroy the disguised information body, you won’t find anything under it. In addition, if you make additional changes to the disguised information body already recognized by the enemy, the enemy won’t be able to aim even at it.Retsu was very proud of it, it was the magic he had put his heart into to achieve the point of being called the “most skilled in the world.”
Tatsuya & Maya Discussing About Parade
Tatsuya asks Maya about the workings of Kudou Family’s Counter Magic ‘Parade’. Maya bursts into laughter and deflects the question by telling Tatsuya that ‘Parade’ is one of Kudou Family’s closely guarded secret and so she won’t know about it. Tatsuya pushes further by saying that she was his student and even though she doesn’t know the Magic Sequence, to at least tell the ins and outs.
Tatsuya presents his own hypothesis about it to Maya – "Counter Magic “Parade” applies Data Fortification on your own Eidos and rewrites or alters your appearance. To be precise, it is a Magic Sequence that applies a different appearance or a fake mask on the Eidos and creates a false appearance, using the new appearance to mask the original in order to protect the real form from hostile magical effects, correct?".
Maya responds by saying that ‘Alteration’ Magic cannot be achieved in the real world. Tatsuya further discusses about ‘Parade’ with Maya stating - "Rather than using “Alteration”, a simple adjust at the visual level using Light Refraction Magic would be enough. The problem lies in that Light Refraction Magic cannot escape my “eye”, hence where the issue lies". Tatsuya further mentions that ‘Mist Dispersal’ was also avoided which surprises Miyuki. Maya replies that then Trident should have no problem.
Tatsuya asks Maya if Parade can be cast on top of itself, to which she reveals that, in regards to Parade, Kudou Retsu’s younger brother was much more adept at it.