Who is Loa?
Long ago, long before mortal creatures set foot on the surface of Azeroth, powerful spirits roamed the lands, creatures inextricably linked to the planet itself, the embodiment of life and nature. At that time only trolls were one of the first intelligent races. And it was the trolls who began to worship the creatures who are called Loa.
The trolls of Azeroth are divided into many tribes: from the forest trolls Amani and ice trolls Drakkari, to the mighty Zandalari empire. But they all have one thing in common - religion.
South Kalimdor, home to the Zandalar mountain range, became a holy place for the trolls, for it was there that many Loa dwelt. The troll priests dedicated themselves to only one patron spirit. Druids drew strength from several Loa, which caused discontent among the spirits, because they do not like to share their followers with others. It is not without reason that the more Loa admirers, the more gifts and sacrifices are made to them, the stronger the Loa become. One of the most revered trolls among their people, the mysterious dark hunters, also possessed the power of several Loa, and could even become conductors of the power of powerful spirits using ritual masks.
Loa can bestow great gifts of strength, wealth, and health on their worshipers. But anger the Loa, and horrible curses will fall on your head. There are legends among the trolls that it was the Loa who gave their followers the amazing ability to regenerate, and those who do not worship the gods may lose this ability. Although many spirits are capricious and fickle, or weak and frail, there are some truly sinister and cruel monsters among the Loa.
A bit story of Loa
Thousands of years ago, a foolish troll summoned Hakkar the Soul Flayer to Zandalar. This winged Loa unleashed a devastating bloody plague on the troll empire that killed thousands of Zandalar's inhabitants and marked one of the darkest periods in the empire's history. Hakkar will return to Azeroth more than once, bringing destruction and destruction. For the Loa are supposedly immortal.
The surface of Azeroth has changed dramatically over the centuries since the trolls appeared. Most of the empires of their people fell under the uncontrollable flow of time, as well as under the swords and spells of other mortal peoples. Their cities fell into ruins, the former greatness of the trolls was lost, one thing remained unchanged: their religion.
However, some tribes have resorted to desperate measures to survive or to try to regain their lost strength. So the Gurubashi tribe captured many different Loa in order to feed them to the returning Hakkar and revive the terrifying blood Loa. When the forces of the Lich King attacked Zul'Drak, the Drakkari ice troll tribe betrayed their gods. They captured the Loa and drank their blood to gain some of their divine power, hoping to stop the advance of the undead army. The Amani tribe also stole the power of their gods to take revenge on the hated elves and resurrect Zul'Aman, infusing this power into their most powerful warriors.
Like other wild gods such as Cenarius or Goldrinn, the Loa are inextricably linked to the Emerald Dream, the spirit world beyond the physical world. When the bodily form of the wild god is destroyed, it soul returns to the Emerald Dream, and over time is restored and reborn on Azeroth.
There is no exact answer to the question of whether it is possible to enslave or kill a Loa, but perhaps there is a way - if nothing is left of Loa's body.
Only one Loa is known, which was finally destroyed. Mam'toth, the Loa of mammoths worshiped by the Drakkari tribe, destroyed himself when he learned that his followers were planning to kidnap his powers. A powerful explosion incinerated the temple of Mam'thoth and all of its treacherous servants, traitors, but no trace remained of the Loa itself. He is considered lost forever.
But the other gods sacrificed to the Drakkari survived this betrayal. For example, Loa Quetz'lun, right before her death, created her own domains in the lands of the shadows, where she dragged all her followers in order to torment and revel in their agony forever, as punishment for betrayal.
Rhunok was sacrificed by his followers during the events in Zul'Drak, but his spirit lived on and appeared to an adventurer.
The Wise Torga - the turtle Loa was killed by blood trolls in Zandalar, but was reborn almost immediately as a tiny turtle.
Spider Loa, Shadra, has died more than once in recent years, but has always returned.
Rezan, the Loa of the kings, was killed by Zandalari prophet Zul and his servants, and then raised his body from the dead, as a huge skeleton creature.
But Loa may not look like animals either. There is a possibility that powerful and respected trolls can become Loa themselves. For example, one of the smaller Zandalari Loa is Zanza the Restless, who looks like a dead troll. Or Bwonsamdi - the Loa of death and graves. Perhaps it because any powerful creatures can become an object of worship for the trolls. So Sen'jin has been hinted at to possibly be among the Loa.
Also it might be some result of unsuccessful experiments by the Titans, like Guun - blood Loa.
In general, Loa is a very broad term that includes a variety of different creatures.