In Dragon Age, all mages are at risk of being possessed by demons and turn into monsters, with the chance increasingly significantly when they let demons teach them magical secrets.
This was considered such a great danger that the church created the Templar Order to watch all mages and prevent them from doing any business with demons, and also to kill all that become possessed. To be effective, all mages need to be registered and kept in the official guilds. Mages who try to hide are captured and held at the guilds, but those who repeatedly try to flee are regarded as being of exceptional high risk to be tempted by demons. So they are garded even more closely and the more radical Templars don't take any risk and execute them before a demon can possess them.
And of course that makes even more mages wanting to get out and considering more drastic measures to escape the templars. And then you have also those mages who are okay with the guilds but suffer the Templar opression because the rogue mages put the Templar on edge all the time.
However, the church is split in two main denomination and the other one has mages as the ruling priest-caste, which is heresy to the other group.
And then there is also a race gypsy elves who escaped from slavery and are not just heathens, which is bad enough, but their shamans are also mages. And they rather die than allowing humans to put their religious leaders in internment camps run by the church.
And there is another civilization in the deep north, who are buddhist communists with the sacred mission to spread their philosophy of doing exactly the job fate has made one best suited for to the whole world. And while they believe that anyone born with magic is destined to be a mage and has the duty to use his powers,
their treatment of mages is even more drastic than that of the templars. And they make no secret at all that they consider it their sacred duty to eradicate the superstitions of all other religions.
So it's no suprise that the world is full of people perfectly willing to kill and torture a lot to keep the world they know safe.