Immediate reactions:
First, shock. Then anger at Feanor that then quickly spreads to his brothers. At some point he will break down weeping, and remain somewhat in shock and torn, until the Dagor-nuin-Giliath starts.
At first he’s also depressed, but this is temporary. It also doesn’t show when he’s fighting Orcs in the Second Battle. He grieves, but he starts and remains pissed off. His father and brothers betrayed and
murdered Amrod. Because Maedhros actually did resist burning the ships, and even defended Amros after he told Fëanor off, Amros forgives him once he calms down somewhat and begins to process what happened. But his other brothers are not his friends anymore, and he will
not forget it. He mostly takes it out on Orcs, but fearlessly shows his anger at Fëanor (What more could Father do to punish him? Kill him, too?) and pisses on his brothers, too. And the audience should feel like they totally deserve it.
When his father is dying, he does mourn, but he’s also angry. He’s conflicted.
His attitude towards the Oath and renewing it:
He starts out conflicted.
He supported the Oath when he spoke to Amrod on the ships. He wants to take the Silmarils and get revenge on Morgoth.
The Oath took his twin away. He hates the Oath.
No, his father and brothers took his twin away. Their treachery is to blame.
But did the Oath damn his brother to the Void, for breaking it? He doesn’t want think so... but he’s terrified of that fate. He hates and resents the Oath and resents his father ... he wants to believe that Amrod escaped, but does that require him to accept that it was OK for his brothers to kill him...? He can’t accept that. But he isn’t sure it’s not true.
He struggles with the above for a bit but in time... he understands. Or he comes to an understanding that lets him cope with the horror. Amros realizes, before his brothers, that this happened because of the Oath, the Kinslaying, and the Doom. Not because Amrod was guilty of breaking the Oath but because they are
all guilty of swearing it. They are Doomed.
So at first he resists renewing the Oath. He argues with his father, fearlessly. But then he realizes... it doesn’t matter if they swear again, because they’re already bound, already doomed. What does it matter if he renews it? He laughs bitterly. He will not renew it to please Fëanor, but he knows it doesn’t matter. He knows he can’t escape the Oath. He accuses Fëanor of leading them all to their doom. In front of everybody, because at that moment he’s past caring about the consequences.
EDIT: (But if we really depict Ep 1 with the sons of Fëanor NOT swearing the Oath, then Amros
has to swear it now.)
His words prompt Fëanor to have the vision... that Amros is right. Fëanor
has led the Ñoldor to their doom, they cannot possibly defeat Morgoth. But Fëanor refuses to admit it, and his other sons don’t believe Amros. (Amros gets away with this because Maedhros is suddenly in charge and even though he’s still 100% in favor of the Oath, he also feels bad for Amros’ situation and doesn’t want to punish him for speaking against Father.)
Medium-term fallout after Fëanor’s death:
Amros is very upset when Meadhros (whom he could accept as a leader) is captured and he’s stuck with the leadership of Maglor, which might really just mean the leadership of Curufin behind the throne. In the camp in Mithrim he sets his tents and his people off to one side. Henceforth, he’s not interested in hanging out with them when it isn’t official business.
When Fingon rescues Maedhros and the Feanorians are finally convinced/dragged into reuniting with Fingolfin's host, nobody wants to talk about the burning at Losgar... or explain where Amrod is... except Amros who just blurts out the whole sordid tale. (Maedhros is still too asleep/unconscious/out of it to explain it himself.)
Morgoth starts a lot of rumors about the misdeeds of the Noldor circling among the Sindar, leading to Thingol's confrontation with Finrod, Angrod, and Aegnor. But the rumor about burning the ships was started instead by Amros. It’s a spiteful act... but it’s also Amros’ unwillingness to hide the ugly truth or defend what his brothers did.
In early Season 04 his depression and rage change into bitter resentment.
His attitude in battle against Morgoth:
He's reckless, and doesn’t entirely care if he lives or dies. He is
not suicidal, he’s convinced that suicide would land him in the Darkness and that terrifies him. He doesn’t even consider betraying his brothers the way they betrayed Amrod. But he becomes... vicious.
He can’t quit the war and won’t sabotage it. He’s still dedicated to revenge on Morgoth. He still wants to regain the Silmarils, but not for his father’s honor.
EDIT: During the Siege he has hope they can prevail for a time, but like Finrod he knows this can’t last forever (though he lacks Finrod’s faith in the Valar). He might say that once on screen, but he need not talk about the Doom. After the Bragollach he has less hope.
Long-term attitude towards his brothers:
If there are machinations between Maedhros and Curufin, Amros is on Maedhros' side, until the Second Kinslaying.
He won’t forgive the others. Sometimes he works at cross-purposes to them, not in sabotaging the Union of Maedhros or the attack on Doriath, but in lesser things. Instead of living just south of Estolad, he lives closer to Amon Ereb, far from his brothers. When they get together for hunting or councils or Mereth Aderthad, he doesn’t come. When they send letters to him, his responses are cold, or nothing. He abrasive or unpleasant to anyone else. It’s only a grudge/feud against his brothers.
When the Dwarves come into contact with the Fëanorians, they first meet Caranthir’s folk. And Caranthir behaves so rudely or puts both feet so far down his throat that the Dwarves are like.... “this guy is a jerkface”. Instead of continuing to taking the north road through Thargelion, they start taking the road due west of Sarn Athrad and trading with Curufin, who acquires
Angrist and is happy.
Then Amros is like, “why are you trading with my brother Curufin, who completely sucks?” He bans the Dwarves from going through his territory to get to Himlad. He thinks that whatever outrageous and obnoxious thing Caranthir did has alienated them permanently (which is a reasonable guess) so now the Dwarves won’t be trade with his brothers and they’ll trade with the sons of Finarfin instead. But Thargelion is such a convenient way to get into Beleriand (now that the direct road to Himlad is closed) that Caranthir (or some smooth-talking vassal of his) manages to talk them around. So they start trading with Caranthir, and it’s so profitable that they’re willing to tolerate him being very rude at random unpredictable intervals, and he’s willing to tolerate their “unloveliness”.
When Finrod, Maedhros, and Maglor go hunting in southeast Beleriand that one time, they pass through Amros’ lands. Finrod tries to entice Amros to participate, hoping to encourage the start of reconciliation with Maglor, but Amros isn’t interested. When Finrod leads the Edain out of Ossiriand he’s bursting with excitement and wants to introduce all the Ñoldor to his new friends. Initially Amros is interested in the Edain, but then Finrod is like “Let’s go show Maedhros and Maglor how awesome this is! And these people need somewhere to live in East Beleriand so we need to talk to your brothers.” Then Amros politely tells Finrod to please take these strange half-naked creatures out of his territory and no thank you, he is not interested in coming along north. So the Folk of Bëor end up in Estolad, somewhat north of Amros’ territory. When his brothers later invite the Edain to ally with them, he pointedly doesn’t, and is very aloof.
In the Union of Maedhros, the Easterlings could theoretically have allied with any of the Sons of Feanor:
- Maedhros and Maglor: ally with the Folk of Bor, who are (mostly) faithful
- Celegorm and Curufin: despise Mortals and are having none of this garbage
- Caranthir: was trying to win over Haleth and is having another go at it now, but isn’t great at making friends as we all know, so he isn’t anyone’s first choice
- Amros: isn’t deliberately sabotaging the Union but is not willing to entirely go along with the program like his brothers, and so refuses to ally directly with any Mortals
Ulfang is left with... Caranthir. We saw where that went. Instead of merely having the bad luck to ally with people who were already in Morgoth’s pay, I prefer the tragedy of the Fëanorians’ behavior being the engine that drives the Curse. Amros’ feud with his brothers (brought on ultimately by the betrayal started by Fëanor) combines with the perpetual unpleasantness of Caranthir to drive Ulfang and his folk away from the Eldar. By being .... crappy allies. Condescending, arrogant, cold ... All things end ill that the Sons of Fëanor begin well, not because the Valar cursed them with failure but because of their own actions. (Maybe Haleth declines an alliance with Caranthir because she forebodes that associating with them would end “ill”.)
EDIT: He still has enough confidence in Maedhros’ leadership to hope the Union can renew the Siege for a time, but after the Nienaeth he loses confidence and starts talking about and quoting the Doom.
Amros continues to alienate his brothers by just refusing to forgive them. For their part, all of them (except Maedhros) are sick of being shunned. All of them (including Maedhros) really Do. Not. Want. to hear about how they’re Doomed and “slain [they] shall be”. That’s no fun for morale, especially after the Fifth Battle. So he’s shunned in turn.
He saves the life of one of his brothers during the Fifth Battle, because despite everything he doesn’t wish death upon them. Before everything went wrong, they were a close-knit family. But that act doesn’t reknit their family after the disaster of the Fifth Battle. What is he left with, after that? He has mostly given up on his brothers, alienated them, and cannot forgive them. The Ñoldor have lost the war. He concludes that the Oath is the only future he has left. Break it or fulfill it, the Oath will be his fate. He has moved from “The Oath is the abstract Doom of the Ñoldor” (which he still believes) to “The Oath will be our personal Doom”.
If Amras takes a position apart from his brothers and in part actually in some kind of opposition (although he fights in the wars), and the Sindar still consider him a kinslayer (rightfully), and the descendants of Finarfin and Fingolfin have similar views of him, then he will become utterly lonely, with just some servants and soldiers, and each encounter will lead to either him rejecting people or others rejecting him. In the end, his only choice, his destiny, will be to accept the consequences of the Oath. The only way to free himself from the burden of the Oath is to join in the kinslayings. He could do this without really being into it, and he could be reluctant to use violence and be one who tries to convince Dior to hand over the Silmaril he carries. In contrast, other brothers, like Caranthir, can be more full of aggression and have no qualms about killing those who keep the Silmaril, even if they are elves. I think he would contain a crucial aspect of the problems of the Oath that the sons live with and it would certainly be a mistake to kill him before the third Kinslaying.
His attitude towards the Kinslayings:
By the time of the Second Kinslaying, he feels some remorse over Alqualonde, but not a huge ton. His moral focus is not on right and wrong, but on guilt and Doom. Remorse doesn’t sway him from joining in at Doriath, nor is it his motivation for going along with Maedhros and Maglor trying to break the Oath. They think they’ve convinced him this is wrong... but
they think the Kinslaying is terribly wrong and the Oath itself might be OK if they can just fulfill it nonviolently... somehow. Amros doesn’t really mind Kinslaying much, but he looks upon the Oath as their Doom. They were wrong to swear it. After they were all wounded at the Nirnaeth Arnoediad but survived, he is certain the Oath itself will kill them, it’s only a matter of time. Maybe it will kill them in battle (so he doesn’t resist attacking Doriath), or maybe it will kill them when they try to break it. It isn’t really in his hands, you see.
He is resigned to die... and so he’s trying to make peace with his twin’s fate and with not struggling against his fate. Not that he’s at peace in general, because he still hasn’t forgiven his brothers (or father).
Maybe, in his darkest moments, when he fears his twin is lost in the Darkness, of breaking the Oath and casting his own soul into that dark, as the only possible way of reunion?
When the war against Morgoth has failed and the Oath has started killing his brothers, who he didn’t actually have a death wish against, he reaches his darkest moment. Occasionally he feels like he’s willing to try breaking the Oath because... if doing that damned Amrod to the Void ... maybe he wants to be reunited with him. (This will be very dark. But it will be a temporary, intermittant attitude.) He is also motivated to try breaking the Oath by spite to spoil/ruin his father’s legacy, now that all the other hopes of the Noldor are ruined.
The Oath torments them something like the Ring tormenting Frodo – the constant intrusive thoughts of desire for the Silmaril, until the light of the Sun and Moon seems sick and dreary. They see visions of themselves being cast into the Everlasting Darkness, and Amros sees visions of his twin who might be there
even now. His memory dredges up that moment when he heard Amrod screaming in Lammoth. (Remind the audience what happened in Season 03.) This should be disturbing. It would be a very contrasting reason for him to try to break the Oath, compared to Maedhros and Maglor who do so out of remorse and repentance.
But Amros doesn’t really, truly want to go to the Everlasting Darkness except on his worst, darkest days. He isn’t morally bothered much by Kinslaying. The pressure/torment of the Oath makes him more unhinged over time until he finally starts to act a bit crazy.
Or it would fit with the suggestion that at the end he degenerates into behaving almost like Crazy!Denethor at the Battle of Pelennor Fields. First, We're all doomed but maybe I want to end up with Amrod, whereever he is, so I'll break the Oath.
Followed by, Those people at the Havens are doomed anyway, Morgoth is winning, why not kill them? 'Slain ye shall be,' so why not die in a Kinslaying? We'll all burn one way or another!
He isn't crazy for most of the First Age, but the strain of fighting the Oath for 26 years finally snaps his sanity. Kind of the way Turin says crazy-sounding things when he finally finds out who Niniel was.
He feels
more at peace once he fully accepts his fate is to die fulfilling the Oath. That’s all kinds of wrong, which is why it becomes self-fulfilling.
And Amros is killed in a fiery scene on the shore, during the Kinslaying, which did involve burning according to Bilbo’s song in Rivendell.
But the audience sees, though he was right that swearing the Oath doomed them, he was wrong that they had to give in to it. Maedhros and Maglor survive the Third Kinslaying specifically because of their reluctance.
His death is not primarily because of Amrod's death, but because of the Oath. Amrod's death was what led him to realize that the Oath had doomed them, and to become the spokesman for the Doom of Mandos.
