Karla the Grey Witch
SPOILER!
Karla is the OVA's most dangerous kind of antagonist because she rarely wants the obvious thing. She does not march under Marmo's banner, does not want Beld to conquer Lodoss, and does not become a hidden ally of Valis. She believes Lodoss survives only when no single power becomes strong enough to dominate the island.
That belief lets her help one side and ruin it later without seeing herself as inconsistent. She can interfere with Princess Fianna, speak calmly with King Kashue, steer the war, and then turn on Beld when his victory threatens the balance she wants. To Karla, kingdoms, kings and adventurers are pieces on a board that has to remain permanently unsettled.
Why it matters
The Grey Witch makes 'balance' frightening. Her goal sounds cautious until the OVA shows how much suffering she is willing to preserve in order to maintain it.
Debut: Ep 004 - The Grey Witch
The Circlet
SPOILER!
Karla's circlet is the real continuity of the Grey Witch. The body Parn and Ghim know as Karla belongs to Leylia, but Karla herself survives through the enchanted band on her forehead. Removing it can free the current host, but destroying or removing the body is not the same thing as ending Karla.
That distinction becomes brutally clear when Ghim succeeds. Leylia is released, yet Karla's will immediately finds another vessel in Woodchuck. The victory is real, but incomplete.
How you can tell
When the circlet remains in play, Karla remains in play. The face can change. The voice and purpose behind it do not.
Debut: Ep 004 - The Grey Witch