Secondary characters would most likely be used in a subplot.
Answer:
Dryads are mythological spirits who make their homes in trees.
Explanation:
1) correct spelling of spirts > spirits
2) Dryads is plural, so you need the pronoun to be 'their' not 'its'
3) I changed home> homes because presumably the dryads live in multiple homes, but it could be argued that 'make their home' is an expression and is acceptable.
4) I would not add a comma before the 'who' because in this sentence it seems that making their homes in trees is an essential part of defining who Dryads are.
