Anime Arms Race! Its like Arms Race, but anime!
Team A was suddenly attacked by Team B. Presumably this means team B is the Badguys, but those details have yet to be written by the Fates. That is you guys - the Fates of Team A and Team B who write the fate of your chosen nation.
Every turn each team will receive one Protagonist, one Supporting Character, and one Character Development.
Protagonist is the equivalent to a main phase project in a typical arms race. You design a character who receives three Traits based on their description and design. Traits typically offer a bonus to the character or characters they support, but it can also do things like add functions not normally available for units. The more narrow a trait is, the more powerful it tends to be. Traits can be chosen directly without the need for a random roll. In addition to traits they have a Power rating, which is determined by a d20 dice. Protagonists tend to a single character. All of their equipment is considered part of the character, but may not be given to other characters outside of Character Development.
Supporting Characters are the bulk of your army, typically representing multiple characters at once. Supporting characters can be anything from the faceless mooks that Protagonists cut down by the dozens to a sidekick to a battleship that a Protagonist captains. Weaker than protagonists despite their numbers, they receive only one trait and d10 Power.
Character Development is this game's equivalent to Revisions. You have to choice to add 1d5 Power or a new Trait to any Protagonist or Supporting Character. This will represent something like a Protagonist training to become stronger, or receiving their mid-season upgrades, or other common cliches depending on the situation and advancement.
There are three lanes, each with four steps. The layout of 2 steps per lane is decided on by each team. You decide which lane to deploy each of your units in, or you can hold them back if you want to (mainly relevant for your Leaders). A partial victory pushes your enemy back half a step to their capital, a full victory pushes them back a full step, and a tie keeps everyone in the same position. You will start with everything at the half-step in the middle of the board. Making it to the final step allows you to attack the Leader regardless of their position.
Combat is decided by adding up all the Power on each side, then adding all bonuses for traits, then adding a random number to each side just for fun. The one with a higher Power in the end is the victor. Units on both side can become Incapacitated in the fighting, with the looser taking a majority of the losses. Incapacitation prevents the Unit from acting for a set number of turns explained to your side during the Incapacitation representing something like the unit spending time in the hospital, repairing their equipment, or being captured. Units may still undergo Character Development but may not be deployed in this state. Which unit is Incapacitated is random but weighted by Traits - if for example an Air Unit is fighting against a group entirely focused on fighting Air Units it is more likely to take an Incapacitation. If a Character takes two Incapacitations in a single fight it rolls two dice to decide how long it is out. If a character takes three Incapacitations then it dies. Death is therefore very rare unless you get unlucky or go up against overwhelming odds.
To achieve victory you must defeat the enemy Leader. Leaders are special Protagonist units that start out with 20 Power and traits that effect your entire army even when they are not deployed. Leaders can be deployed to the frontline like normal units, but will have a high odds of Incapacitation as the enemy Units will tend to aim for the high value target. Incapacitation removes the effects of their Leadership skills for the duration. Reaching the enemy capital with any of the three lines allows you to attack the enemy Leader even if they aren't deployed, are deployed elsewhere, or are incapacitated.
So what exactly makes this anime, Stirk? It is you my dear readers. While most arms races assume the game takes place in something close to reality this game assumes by default everything is happening in generic anime land. Don't be afraid to use cliches. Advanced technology and powerful magic are assumed to exist but not really make a difference since a school kid with a sword can cut through robots and golems as easily as they cut through a peasant with a pitch fork. It is assumed that you will need to fight directly up the lines without bypassing any - but otherwise the flavor of your nation and units is cast in a broad anime-style brush.