Basic Combat, Ship Design, and War

This guide is intended to show how I approach war and ship design in Stellaris. This is likely not the optimal method, just how I prefer to do it. I will try to keep the ship designs up to date with the meta, but I cannot guarantee it.



General Combat Overview:
The goal of combat is to kill your enemies, so lets cover how combat works. There are four weapon types: kinetic, energy, explosive, and strike crafts. Ships have three health bars before dying: shields, armor, then hull. After the shields are depleted, the ship takes damage to armor, and after the armor is pierced it takes damage to its hull. Once it loses all of its hull, it dies. Shields takes more damage from kinetic weapons, but takes less from energy weapons. Armor takes more damage from energy weapons, but less from kinetic. Hull is not good against any weapons types, but several of the more specialized weapons of each weapon type deal bonus hull damage. Explosive weapons (missiles and torpedoes) as well as strike crafts have a special ability where they ignore an enemy's shields and starts damaging the armor directly.

There is a few weapons that ignore both shields and armor, doing damage directly to a ships hull. Hull damage also provides a secret debuff to a ship, lowering both its movement speed and its fire rate. There are also special weapon slots called point defense (PD). There are two trees of PD, one called point defense and then flak. Don't worry since flak is worse and there is no reason for it to exist. PD is used to shoot down missiles and strike crafts. This can be useful for countering enemy fleets if you know they will be relying on lots of missiles. I haven't really talked about strike crafts but they are space fighters that bigger ships can carry.

tl;dr damage goes shield -> armor -> hull. Hull damage debuffs and kills the ship. Kinetic kills shields, energy kills armor. PD to counter missiles and fighters.

Disengagement: This is an annoying aspect of combat, but ships have a chance to flee a battle if they take damage while below 50% hull. The AI also get a significant boost to disengagement chance, so expect most of their fleet to flee instead of die. Fleeing also means your opponent doesn't get as much war exhaustion. This is primarily something you will have to deal with in the early game, since larger ships have a lower chance and high damage weapons can kill in fewer hits..



Ship Design:
Be aware that this section might be out of date and is unlikely to be optimal. The optimal late game fleet is likely pure battleships with neutron torpedoes and kinetic artillery. Against the AI and its ship design, the optimal ship design is not required. Be aware that the various endgame crises have different weaknesses that you should retool your ships to take advantage of.

Next lets talk ship types; there are four (five with Apocalypse DLC) different sizes of ships. Corvettes are the smallest and your starting ship. They are the fastest ships in the game and have a high evasion score (which is compared against the accuracy score of the ship+weapon shooting at it) meaning they can dodge big guns like in your Japanese animes. Early game it is best to use the three small weapon configuration since the AI currently stacks PD like crazy. I use kinetic with two lasers. Replace the kinetic with autocannon and lasers with plasma as they become available. Against fleets with few PD, one of their best configurations is a small kinetic front and missile back. Optimally these should be an autocannon front with a torpedo back. This can be very effective against the largest ship sizes since the corvettes cost less to make, and can dodge the larger weapons. Corvettes are also useful for anti-piracy patrols if don't have enough coverage from starbases. Corvettes are the fastest ship in the game and, when combined with afterburners (which increase speed even more), a side fleet of corvettes can be very useful to quickly capture lots of enemy systems while your main fleet hits starbases.

Destroyers are the next ship you research and can fill multiple roles. Early game you might prefer to put a large kinetic with small lasers behind so that it can do bonus damage to an enemy fleets' shields then do bonus armor damage with its lasers once they are down. After cruisers appear I retool them to have a large kinetic front with PD on the back section. I also set their computers to medium, so they can protect my cruisers from enemy missiles. My optimal late game destroyer uses a kinetic battery/artillery front with PD back and a medium range computer.

Cruisers are supposed to be the mainstay of your fleet but Paradox is terrible so it is the opposite. Despite having lots of different section types, I prefer my cruisers to be all medium slots with energy weapons in them. My strategy is to have the destroyers take down shields with their longer range kinetics, and my cruisers to then burn through the armor to that sweet center. Ideally I would like plasma for the energy weapon slots. Don't build very many since battleships are superior. Cruisers are slower and thus have less evasion then smaller ships, but don't have the range and damage of battleships.

Battleships are big and get access to XL weapons. I prefer to have an XL front with all other slots being large. I put an arc emitter (which is XL) front and fill the rest of the slots with proton/neutron torpedoes (which are actually energy weapons despite the name). Since they are slower then the smaller ships, by the time they get in range the destroyers should have taken down the enemy's shields which is why I go all energy. Put a long range computer on them for the range bonus so they can shoot sooner. If you know that you will be up against a fleet of smaller vessels, like corvettes, it might be better to use the comp that adds a bonus to hit, to help overcome their evasion score.

Titans are from the Apocalypse DLC and have an unique titan sized weapon, the perdition beam. This is an energy weapon that can literally hit across a star system. I fill all other slots with neutron torpedoes for the same reason as the battleship. You are limited in how many titans you can build, every 200 naval cap allowing you to build 1 more.

In terms of fleet construction, I don't like corvettes once I get cruisers. This is PURELY A PERSONAL PREFERENCE. I like fleets with a mix of 3 destroyers per cruiser, and 1 cruisers per battleship. If I use corvettes late game I usually go 1:1 between corvettes and destroyers. I only do 1 titan per fleet since I like them to be flag ships. They will also slow your fleet down noticeably.

tl;dr ships go corvette -> destroyer -> cruiser -> battleship -> titan with each larger ship size being slower. Corvette: Kinetic+missile(torpedo); Destroyer: large kinetic front, laser back earlygame, PD back lategame; Cruiser: all medium energy(plasma), drop lategame; Battleship: Arc Emitter, neutron torpedoes; Titan: Super laser, neutron torpedoes. 3:1 Destroyer:Battleship



General War Advice:
I don't like to go to war until I have destroyers produced. Before that it is hard to get enough fire power to destroy an enemy starbase without painful losses. When declaring war, be careful and check to see if they have a defense pact with any other empires or have their independence guaranteed by another empire. If you are facing a situation where multiple empires have overlapping defense pacts, either try to insult the weakest or look to see if one empire has less defense pacts. Be aware that you will take casualties so make sure you have a shipyard near the conflict region and a healthy stockpile of alloys. If you are in a defensive war (or you think you can bait them) try to engage the enemy fleet within range of a starbase you control. This adds a little extra damage, especially if you happen to have defense platforms. When agreeing to a status quo in a war of conquest, only systems with claims that were conquered will change ownership. To conquer a system you must control the outpost/starbase and all planets (if any) within it. Also beware that the AI often makes bad planets, and conquered worlds will take a 10 year penalty to population happiness. Conquering too many worlds can easily crash your economy.