Order

Order is a mysterious concept in the lore of Dota 2, often spoken about by entities of cosmic consequence or other lesser beings who may have an affinity for it.

Description
Order is the antithesis of chaos, which means that order is what makes up existence and creation. Order can be made from chaos and vice versa. Order itself is vague and information about it is sparse, but it does encompass the following stuff compared to its counterparts in chaos. Note that some of them may not have a known counterpart yet. It is said to have different levels, both high and low. Reaching higher levels of order is accompanied by enlightenment  while dying in some ways causes one to achieve a lower state of order, although it may only apply to forces of chaos who can actually bring others into lower states of order. There is also an ultimate level of order which seems to be achieved in death. This ultimate level of order may refer to the final harmony that all beings achieve when they die. It's possible that this final harmony is the unknown plane of existence where everyone is interconnected to each other.

It is also an afterlife as well as a source of restoring one's existence from death or chaos or a source of renewal for those who have access to it.

Notable Entities
It's interesting to note that just because the following entities are aligned with order, it doesn't mean that they don't have some form of chaos to their existence. That's the essence of duality, after all.

Heroes
seeks to establish universal order in the form of harmony, wholeness, and unity through the Great Unification, where he will unite the fragments of the shattered Primordial Consciousness, which includes Radinthul and Diruulth. As a force of order, he disdains the stuff of chaos (and others who bring it ) such as disunity and disharmony, although he isn't appalled enough by it to prevent himself from exploiting his own disunity.

is a member of the ancient Order of the Oyo, an esoteric faction dedicated to a mission of a lifetime that has spanned for generations of Brewmasters before him: to find the answer to a single paradoxical thought that the divine consciousness known as The Wailing One couldn't think and hence split all of existence into disharmony. Like all Brewmasters before him, he searches for enlightenment through imbibement to find the single thought that would unite the great rift between the material and spiritual planes once again. is the sole herald of the Children of Light, who once strived to spread light to the cosmos and bend chaos to order. Even in her weakened state, she still possesses the ability to create order from the chaos found within each scene of strife to recharge herself.
 * Just like some of his Celestial brethren, he also desires to achieve balance, which is encompassed by order.

Among the Celestial brothers, only the, the , and the value order. Raijin has absolutely nothing to do with this order, especially with his jovial and rebellious nature. However, all four Celestials were complicit in Sun Wukong's punishment for disrupting the cycle of nature, demonstrating their affinity to order. Among the five Founders,, , and are aligned to order. claims that gods can forge order from the chaos. It's unknown if this applies to all kinds of gods outside of his pantheon or to his own pantheon only.
 * Kaolin believes in concepts of order like harmony, wholeness, tranquility, truth, etc. He also believes in orderly cycles such as the oscillation between life and death and the great wheel, also known as the great cycle or the cycle of nature.
 * Xin believes in harmony, balance, destiny, tranquility, discipline,  etc.
 * Inai is not so explicit with his affinity to order, but he does encompass fate and balance (not to mention that his machinations usually involve control, planning, and calculation, which inclines to order) and finds no ally in those aligned to chaos. He seeks to avert the chaos that he only knows as The Great Confluence.
 * Although Elder Titan was responsible for compromising the world's wholeness by separating it, he still seeks amends for his great mistake and yearns for unity and wholeness once again. Those who are slain by him are returned to Unity  including the four Fundamentals.
 * Enigma may not look the part, but he is aligned to order. Like his creator, he seeks to reunite something that was torn asunder, possibly referring to the great rift that encompasses all of existence. Those who are slain by Enigma achieve final harmony/returned to Unity. Not to mention that gravity is a force that keeps things together, hence the Unity theme.
 * Ezalor is the antithesis of chaos. His lines towards Chaos Knight suggest that he can bend chaos to order.  Such was his quest that his solar descendants followed in his footsteps to keep chaos at bay.
 * However, he is implied to be responsible for disrupting the Primordial harmony that bound the 4 Fundamentals together in their realm. That definitely doesn't sound like order...

Factions
Just like their most prominent member, the Order of the Oyo seek to find the one thought that would unite the shattered world that we live in. The Aesthetes of this order gather in holy reverie atop the peaks where the wheel books are to anticipate the song produced by these books when the sacred wind blows upon it. The books sing about a great rift that encompasses all of existence, which was made after The Wailing One conceived a single paradoxical thought. The Wailing One could not think this thought and become one being, rending it asunder and creating the multiplanar universe of the Dota 2 world.

DOTA: Dragon's Blood
In this continuity "order" essentially correlates to the strong nuclear interaction.