EDIT: It's quite possible that you're talking about a comic here...most of what I've written in this post does still apply. Adjust as needed.
Right...this is going to get a bit complex.
The planning groundwork you've done is right and good. I think the problem is that you're still staring at the foundation you've created and you're not thinking as much about the house that needs to go on top of it, so to speak.
So, any combat scene in a book is a storytelling tool. It's not a flashy action beat that exists to wow the reader - it's a sequence that's telling a story just like any other scene. So, what you need to figure out now is:
Who are your point-of-view characters for this sequence?
What narrative events and emotions are they going to experience as this sequence progresses?
Now, the benefit of prose is that you can get right inside your character's heads in a way that you can't do in a movie or television show - so, when a character has an "oh shit, my friends are about to die!" moment, you can actually have a paragraph where s/he desperately runs through options in their head, rejecting each one in a rising panic. Likewise, you can have a paragraph where somebody is coldly calculating out every move.
The first major action sequence in my book finished up two weeks ago. I'll link to them, and after the links break it down.
So, we've got a fight with seven involved characters, five of which have point of view status. They are:
- Atria Silversword
- Princess Stella
- Adam (Stella's fiance)
- Captain Infinite
- Jack Death
Jack Death is an observer - the only thing he does is watch Captain Infinite descend from the sky at the beginning of chapter X. The only reason his POV section exists is because it's groundwork for a payoff in a later chapter where he joins one of the sides. This leaves us with four characters.
Atria is our main POV character for most of the fight. She is a military officer and a mech pilot, so she tends to be very tactical and calculating in her thinking. She's also emotionally clinging to her friends Stella and Adam for dear life, so she is going to put them first.
Stella is the secondary POV character, but she is functionally out of action as of the end of chapter IX. She's very smart, but feels useless because all of her instincts are that of JRPG combat support mage while all of those powers are long gone.
Adam is a supporting POV character - his POV section appears briefly at the beginning of chapter X, and it is used because he is the only one of the POV characters who will recognize Captain Infinite when he shows up (other than Jack Death, who is not likely to give the reader much of an introduction, and Jenny Calhoun, and Jenny is not a POV character for this fight), and thus the only character who can give the reader a proper introduction to Cap when he appears. After that, he is no longer relevant to the scene.
Captain Infinite is a secondary POV character, and to a degree he replaces Stella as the second POV for chapter X.
That's the characters. Now let's break down the structure of the fight.
Chapter IX
Atria, Stella, and Adam encounter the Destroyer and Jenny. Atria tries to negotiate, negotiations fail, and the fight begins.
From Atria's POV: Jenny Calhoun engages her and matches her stroke for stroke. Atria begins to worry because she realizes that Jenny is probably going to win. Jenny gets the upper hand, pins Atria, and Jenny's knife presses against her throat.
From Stella's POV: Stella sees Jenny fight Atria to a standstill, leaving The Destroyer alone. Stella becomes desperate and decides to bluff. The bluff doesn't work, and The Destroyer exposes Stella and Adam and sends a spike of masonry speeding towards them.
The action of the fight this chapter thus moves from the protagonists thinking that it will probably be an even match to all of them down and about to die.
Chapter X
From Adam's POV: Captain Infinite appears, saving the day. Adam sees Cap start fighting The Destroyer.
From Atria's POV: The shock of Cap's arrival allows Atria to get out from under Jenny's blade. Jenny reveals that once she kills Atria, she'll kill Stella as well, increasing the stakes. Atria, despite being winded from the fighting so far, becomes more resolved to win and keep her friends safe.
From Cap's POV: Cap fights The Destroyer to a standstill, realizes that they are evenly matched, and manages to knock him geographically away from the fight with a well timed blow. He returns to the alley where the others are fighting, finds that the McGuffin the fight is about is now unprotected, and discovers that it is leaking the very radiation that he is vulnerable against. Something hits him in the head, knocking him to his knees.
From Atria's POV: Atria is holding her own, but slowly losing ground and realizing that she can't win this fight. She becomes desperate for some opening she can exploit, but none comes. Cap returns, and Atria experiences hope, because now it's two (Cap and her) against one (Jenny). However, the distraction gives Jenny the opening she needs, and she cuts open Atria's side. As Atria reels from the blow, she sees The Destroyer return and incapacitate Cap. Now she experiences despair - the fight is over, and there is nothing stopping Jenny from killing Stella. Atria begins to beg for her friends' lives. By some miracle, The Destroyer decides that he and Jenny have to leave. They leave, and the fight ends.
So, we start the chapter with hope restored - Captain Infinite appears, the tables are turned. Then, there is another reversal. And then, the fight ends, and the protagonists must now lick their wounds.
If I've done my job right, the reader will figure out that the reason The Destroyer ends the fight is because he realizes that Cap isn't actually down for the count as Atria fears, and so long as Cap is there, there's too much danger of his side losing and Jenny getting hurt. But The Destroyer and Jenny are not the POV characters here. We'll get Jenny's impressions of the fight in a later chapter.
The actual moves of the fight are almost irrelevant compared to what the POV characters experience, what is revealed about their true selves in the experience, and how this sets them up for later growth. So, we see Atria think she has everything under control, realize that she doesn't, and reach the point where all she can do is beg Jenny not to kill her friends. She doesn't ask for her own life, because that's not who her true self is - she is somebody who will sacrifice herself to save her friends, even if that means doing it on her knees. In future chapters, her growth will come in the form of trying to become stronger and learning as many lessons as she can from this fight so that she can win the next one.
At the beginning of the fight, Stella still thinks that her instincts as a combat support mage can help, but as the fight goes on and she nearly gets herself and Adam killed, she realizes that the only thing her instincts can now do is put her and the man she loves in danger. In the wake of this fight, she has to come to grips with the fact that her powers are truly gone and her role in whatever follows will never be able to be what she once was.
So, what I would suggest is to pick no more than 3-4 characters to be your POV characters. They need to be people who will see the key moments of the fight. Then, figure out what they are going to experience as the fight goes on - what extremes it will push them to, and what this will reveal about their true selves. And then, figure out how this experience will push them to grow as characters, and what change it will provoke in them.
And then, tell the fight through their eyes and their experiences.