Heroes who have picked up this handy skill have the ability to tap into any local magical field in order to produce the illusion that there are suddenly multiple copies of themself. So long as there is a magical field within the battlefield the Hero find themselves able to use this skill.
At first, the Hero can only produce a single, weak and unconvincing copy of themselves, but in time and practice, this copy will become convincing to the point the enemy cannot decipher which is the real hero and which is the fake. While confused the hero can strike hard while the enemy's defenses are compromised.
With training and time, Heroes can summon multiple, convincing copies of themselves, driving enemies to thrash insanely at thin air, while smarter monsters can sometimes find it within themselves to retreat and regroup before the Hero has time to put together a fatal combination of moves.
A note of warning though: The Philosoraptor, being a master of illusionary attacks themselves, are extremely hard to fool with this skill. Heroes would be wise to utilize other skills against this foe, if they had the wisdom to execute such forethought, that is.
Second note: There have been times when heros froget which one is real and fight the clones, just watch out for that.