Light matter:
Makes Hatchling stronger (mentally and physically), causing them to fight to defend themself.
Too much makes them violent and emotionless. Hatchling will want to kill for revenge.
When under the influence of enough light matter, Hatchling will be completely covered in nothingness, and when touched, whatever touches it will be consumed by the void. Results are deadly/fatal.

Dark matter:
Makes Hatchling weaker (mentally) and stronger (physically), causing them to feel depressed.
Too much makes them easy to manipulate and make irrational decisions. Hatchling will want to forget the past, as it makes them feel bad.
When under the influence of dark matter, Hatchling gains the ability to void any objects from a certain distance, as the void is inside them instead of outside. With enough power (which could end up crippling Hatchling), Hatchling would be able to void a person. Results are deadly.

——————————

Too much of either will break them.

Cure: The opposite matter???

Either way, if Hatchling interacts with light or dark matter, it can burn them and be painful.

Hatchling is currently under the influence of dark matter.

Hatchling requires daily doses of either matter to stay in that state.