Greetings all, and welcome to my post!

After a small hiatus due to some unexpected things, my group is doing a one shot in 5e, and I am the DM. If they like how it goes, it will turn into a campaign.

The background for the world is that there was a city called Biafora, but everyone outside of it called it The Godless City due to the fact that magic and the gods were cast aside for more modern features. One of those features was a form of electricity called arcanium, powered by a gigantic magical crystal that the citizens did not know about. As the city grew in power and population, cities and towns took notice and followed suit. Because of this, those crystals were absorbing magical energy from the world, and it slowly began to rot away, leaving the world a wasteland. Due to the more tangible way things could be accomplished, the gods lost most if not all of their worshipers, and thus their power.

The players do not know this, their story is they came back from an adventure, went to a tavern to celebrate, and passed out due to the festivities. This is not the case. The truth is, is that a man poisoned their drinks to kidnap them, and run experiments, for he saw what was becoming of the world.

The players will wake up in a pile of corpses, and have to make their way out of the dungeon to see what the world has become.

My plan is to have the characters quickly discover that they have glowing blue marks all around their body, as well as a gem embedded in their wrist (if anyone knows the game Ark, it looks a lot like that).

TL:DR, What I want is some sort of random magical effects that'll happen to the characters under stress (low hp, casting a spell, using a major ability). Good or bad, might be class specific, might not.

If you have any questions please let me know!!!