The South is a cursed land which slowly drains you of your Northern resilience and genetics.  Once you have attuned to The South you are unable to remove this attunement, even with spells such as remove curse or wish.  For every year you spend in The South, your genetic makeup becomes 1% more southern as the curse slowly erodes what you once were. For example, if a mountain dwarf from the northern tundra lands spent too many years in the southern sylvan forests, they might essentially end up as an elf, albeit a small, grumpy, bearded elf, losing all the racial traits of its former race and gaining all of those of its new race. Your DM will decide exactly how this affects you.

Additionally, once attuned to The South, roll a constitution saving throw at the start if each week.  The DC for this saving throw starts at 1 and increases by 1 each week until you fail a saving throw, at which point the DC resets to 1.  On a failed saving throw you become inflicted with the Curse of The South, a random ailment that simulates one or more symptoms from a common disease such as a cold, flu, chest infection or glandular inflammation, and drains you of a physical or mental capacity.  Roll 1d6 and consult the following table:

1. Strength
2. Constitution
3. Dexterity
4. Intelligence
5. Wisdom
6. Charisma

Whilst under the effect of The Curse of The South, all ability checks and saving throws relating to that ability are made at disadvantage.  Even if you would otherwise gain advantage on that check or saving throw from another source, the Curse is so strong that it ignores that and these rolls are always made at disadvantage. Your DM will decide the specifics of how this curse manifests.

Each day after you have been afflicted with The Curse of The South make a constitution saving throw at dawn.  The DC for this saving throw starts at 20 and reduces by 1 for each subsequent day.  On a failed save The Curse persists, on a successful saving thrown you fight off the effect of The Curse and are no longer rolling at disadvantage on the afflicted ability, but you may well still feel like poop for a number of days.

It is possible to be suffering from multiple Curses of the South at once if you have particularly unlucky dice rolls.

Notes: living in it for a period of 10 years which will irrevocably attune you to it, though you can voluntarily attune yourself to The South before this period has passed by believing that The South is nicer than The North, Debuff, Cursed