Starborn Queen of Queens

They didn't have to include all the parallels between Karen and Frank in DDBA s2, but chose to do so for the "Karen is turning into Frank" character arc.

They didn't need to include Karen in OLK and instead could have had that scene between Frank and Maria, yet they chose for that pivotal scene to be between Frank and Karen. They chose Karen to be the one to pull Frank out of his darkness. They chose Karen to be the one to set Frank up for what he needed to do next and who he needed to become. They chose to show that Frank has romantic feelings for Karen and that he's in love with her.

Considering Frank never moves on from Maria in the comics, I don't see why they would have him move on in the TV show to not make Kastle happen. It doesn't make any sense. Sure, Frank not moving on from Maria is a defining aspect of his character in the comics, but so is Karen being dead a defining aspect of her character, yet the writers chose not to go that route in DD s3. Frank and Karen don't even interact in the comics, yet they're frequently together in DD s2, The Punisher s1, The Punisher s2, DDBA s1, and The Punisher: OLK. They can clearly change things around as they see fit, which is what they seem to be doing with both Frank and Karen's characters.

Putting Kastle together to kill off Karen also doesn't make sense because what would it serve? To further break Frank? He's already broken from his family's murders. He doesn't need to be further broken to serve any meaningful plot points. And saying that Karen's death would break Frank is just proving that he's moved on from Maria and is in love with Karen, otherwise, her death wouldn't impact him the same as Maria's.

First off, I don't care if Elain is Made, if she were going to wield the Dread Trove, then she would have been the one to find the Dread Trove. Nesta found the Dread Trove, and more than that, the items have chosen her. Nesta said herself that the Dread Trove answers to her, obeys her - not Elain. Bryce said the Harp was left for a Starborn - not a Made individual - to find. The Harp was left in the Starborn chamber, which Elain has never even stepped foot in and there's no evidence to suggest that she could anyways. Nesta literally woke up the Harp from its 15,000 year slumber. Nesta found the Harp on former Dusk Court territory during an unintentional scrying, during the Dusk service, in which she heard the sound of the Dusk Court and saw what the land used to be. Starborn/Harp/Dusk Court/Valkyrie all belong to the same person: Nesta.

Secondly, why would Elain world-walk? She has no tie-in to another world. She has no friends or alliances in another world. You know who has both of those, though? Nesta. Nesta's silver flames already tie her in to both ToG and CC, and Nesta has already befriended, created an alliance with, and saved a whole other world. Nesta also has so many parallels with ToG and CC characters. Nesta also has Death-Maiden powers just like Yrene (ToG) and Bryce (CC). Nesta also seems to be watched by the Prince of the Pit and the Prince of the Chasm of Hel. Then there's the fact that Amren told Nesta when she erupted to make sure all worlds felt it. Cassian said he would find Nesta in another world. Bryce said all worlds shuddered when Nesta's hand passed into Midgard to give her the Mask.

I'm not saying Elain won't be important, but if any character is going to use the Harp to world-walk, it's going to be Nesta.

BOROMIR + his bond with Merry & Pippin The Lord of the Rings: The Fellowship of the Ring (2001)

BONUS:

Nesta: *tends to her every need and risks all potential relationships to defend and protect her*

Nesta: *doesn't bother anyone by dealing with her trauma her own way*