If you have a society that integrates magical and non-magical people then within a generation or two you are going to find that:
- Some Mages will abuse their power and become tyrants and hold the threat of unleashing their powers (or even their death-throes) over their community to gain a superior status which will cause a general vilification of Mages.
- Even without that, the non-magical population will be afraid of Mages as Mages will die unexpectedly (as even apparently health people sometimes have unexpected heart attacks or fall down the stairs) and then everyone within several kilometres may also die. If there are multiple Mages within the area then chain reactions may occur following the first death.
The 98% of society (i.e. the non-magical) will want to contain the excesses of the 2% (i.e. the magical) and a portion of that 2% will probably agree with it.
Option 1: Mages are killed
Who wants to live with someone that may suddenly die of a heart attack and wipe out the nearby neighbourhood?
As soon as someone starts to manifest magical powers they are subdued and taken far from society to sacred/traditional place in the wilderness where they will be killed so that their magic can be "harmlessly" released (obviously not without harm to the Mage but so that the harm to society is eliminated or reduced).
Option 2: All Mages must be undead
If the transformation to the undead does not trigger the death-throes of Mages and the undead are less likely to expire due to unexpected medical issues then Mages may be forced to become undead (for the good of society and themselves).
Once the biggest issue (dying) is dealt with then Mages can be trained to work for the betterment of society (although maybe on the fringes of society) and given all reasonable comforts so that they continue not-dying.
Option 3: Mages are forced to the fringes of society
No-one wants to live with an unexploded bomb. Let alone next to 10 or more unexploded bombs that may cause a chain reaction when the first "detonates".
Mages are forced out of non-magical society to live away from the normal population.
This could take the form of:
- Shunning the Mages, although that risks alienating them and causing Mages to retaliate against society.
- Giving Mages remote places to live (isolated from other Mages) and the society supplies them with everything necessary for their continued well-being (maybe even luxuries) on the condition that they stay in that remote place. Different societies could implement this differently with Mages being lone hermits in one country, worshipped as part of the religion in another country or given palaces somewhere else.
- Guilds of Mages (again away from main society) where they can be trained to control their powers. However, this may be risky as one Mage dying unexpectedly may cause a chain reaction with the rest of the guild.
Option 4: Mages as suicide bombers
A combination of options 1 and 3, Mages are identified at an early age and removed from society to multiple remote locations where there only company is a small number of non-magical teachers who indoctrinate them with the "good" that they can do in helping fight the neighbouring countries (which are obviously "evil") by travelling there and sacrificing themselves.