The Abyss

The abyss has a thing where it like changes people if they are in it for long periods of time. There are magical exceptions to prevent being changed. This magic is actually using the abyss, or the void. The best comparison is it is like the Shadowfell of the land. Creatures that come from the abyss have fish like features but some have been noted to have animalistic features. Scales are common and it is not unusual for them to have reptile esque features.