Someone asked for a list of OC characters as a reference, so here it is. I think most of these characters appear in this part of story eventually, at least briefly. But these are the major OC characters in the story overall so far.

Lindomiel—Thranduil’s wife / Legolas’s mother
Dieneryn—Thranduil’s mother and advisor / Legolas’s paternal grandmother
Engwe—Thranduil’s uncle and advisor/ Oropher’s brother (Engwe’s wife, Ormeril, and son, Ninglor, are both dead)

Aradunnon—Thranduil’s younger brother and troop commander
Amoneth—Aradunnon’s wife / Lindomiel’s best friend from childhood
Dolgailon—their oldest (adult) son /a Captain of Thranduil's warriors
Galithil—their youngest son

Amglaur—Lindomiel’s father / Legolas’s maternal grandfather
Limmiel—Lindomiel’s mother / Legolas’s maternal grandmother

Hallion—Thranduil’s steward (Hallion’s wife, Moewen, and daughter, Laugoneth, are both dead)

Celonhael—one of Thranduil’s advisors
Ollwen—Celonhael’s wife (a Silvan elleth)
Duinion—their oldest (adult) son (he is dead)
Berior—their youngest son

Golwon—one of Thranduil’s advisors
Isteth—Golwon’s wife (a Silvan elleth and scribe in Thranduil's court)
Eirienil—their daughter

Crithad—a tool maker and stone worker (one of the architects of the stronghold)
Merileth—Crithad’s wife
Arthiel—their oldest (adult) daughter and Dolgailon’s wife
Brethil—their youngest son / Legolas’s friend

Dollion—Captain of the palace guard / Aradunnon's best friend
Aewen—Dollion’s daughter / Eirienil’s friend

Dolwon—a Silvan elf, originally from the south of the realm, being held in the capital for crimes committed in Part 3.
Lalfien—Dolwon’s wife
Noruil—Dolwon’s son

Dannenion— a Silvan elf, originally from the south of the realm, being held in the capital for crimes committed in Part 3
Eregeth—Dannenion’s wife
Anastor— Dannenion’s son
Maidhien— Dannenion’s daughter / Anastor’s twin

Tulus—a former member of Thranduil’s guard / a Silvan elf, originally from the south of the realm, being held in the capital for crimes committed in Part 3.
Glílavan—Tulus’s adult son and a lieutenant under Dolgailon’s command

Marti—a long term trouble maker (she has also used the names Manadhien and Manarindë so far in this story)

Other characters:

Conuiön—Captain of Thranduil’s personal guards
Túreden—Lieutenant of Thranduil’s personal guards
Colloth—Aradunnon’s guard
Galudiron—Dolgailon’s guard
Galuauth—other member of the King’s guard
Belloth—other member of the King’s guard
Hurion—other member of the King’s guard
Pendurion—other member of the King's guard

Tirithion--archery master in Eryn Galen
Hebor--hand-to-hand combat master
Langon--sword master
Pathon--scout / teaches tracking in the training program