Terraria: King Slime Boss Fight Guide

King Slime is the very first, and by far the easiest, boss to defeat in Terraria. It has the ability to spawn itself naturally through the slime rain event, or it can be spawned by crafting the spawn for it. To make the spawn for King Slime, you will need 20 gel and a crown. The crown can be made from 10 bars of Gold/Platinum and 1 Ruby.

Once you have your way to summon King Slime, you will just need to have your equipment on the ready for when the battle begins. It is an easy boss fight, so I don’t recommend an arena, but if you feel like making one, the arena design is up to your choice.

Let it be noted that King Slime has a pattern to his fight that can be used against him if the player(s) can read his movements.

When King Slime spawns, he will spawn just outside of view range of the player. Quickly check either your left or your right side to find him. If you don’t find him on the side you checked, he will do his initial ability to warp to a player. If you do find him, stay close to him, but just outside of his range.

Once you are close and just outside of his range, remember to back up when he goes to jump. His AI is very similar to normal slime enemies. The difference with King Slime is his ability and that he has a delayed long jump. King slime will jump at the closest player repeatedly. When it comes time to his 4th jump in a row, he will use a long jump to gain a lot more vertical height to his jump. If the player is too far from King Slime or has trapped King Slime, he will use his warp ability to shrink down and teleport near a player, then regain his size.

The key to beating King Slime is to stay close and monitor the amount of slimes currently on the ground that can stop your run path. Count his jumps so you know when he will long jump. When he goes to long jump, you will have more than enough time to run under him and clear out some slimes to get you some running ground. Keep repeating this process through the fight and if done right, he will never use his warp, and you can grind him down to the gel resting in your inventory.

Be careful however. If you do decide to use an arena, or do this strat and do not clear your runway, you might be taken back by King Slime’s auto mechanic. As you damage King Slime, he will get faster and faster, on top of the fact that he will also start to reduce the time between jumps and the height of his long jump. As he gets lower on health, remember to pick up your pace to match him and his speed.

Out of all of the gear I recommend, you actually only need roughly 10 items in specific.

Weapons are up to your choice, as this will be your first trial in boss fights. If you want dps, use summons and various magic staff weapons. If you have bows or other ranged weapons, they will do well to have either good damage or multihit/pierce projectiles ready. The most available piercing ammo for bows are Jester Arrows.

Recommended Weapons:
Grenades – They work very well in doing high damage and clearing out slimes. Only warning is that if you are too close to the explosion, you could damage yourself badly.
Magic Staff – Wand of Sparking does good because of the burn status, but in terms of damage output, I recommend one of the gem staff weapons. Obviously whichever one has more speed and damage, as you will be fine getting mana since defeated slimes will restore it if you are low on mana.
Melee Weapons – Honestly, I wouldn’t recommend melee if you decide to do arena-less. If you decide to use melee, go for it, cause it does still work. I just recommend staying out of his range. However, your best melee weapon for King Slime will be the Mace/Flaming Mace. They can be found underground in Golden Chests. Other melee weapons work, but through my many test fights, the Mace did numbers in helping.
Ranged Weapons – Any, so long as you have plenty of ammo to keep using them. Shurikens work extremely well, so use those if you have them.

Recommended Equips:
Running Boots – Any of the boots work, whichever version of them really doesn’t matter, but atleast having that ability to run makes it much easier for getting speed to escape if your health gets low
Band of Regen – With this equip, you can heal at a quicker rate, which means the longer a fight goes on, the more HP you technically have available
Shackle – It’s just for a defense boost. nothing else to say about it.
Armor – Any, just so long as you have some defense to your name so you don’t take raw damage numbers. Also pointing out, your HP can be any number, whatever makes you comfy on your health.

If the recommendations above still are not helping you or your team out, then you can always go to making whatever arena helps you the most. I found will testing that I could consistently have more HP at the end of the fight when I went without an arena.

My most successful tests, that being tests that ended with less hits taken, more HP leftover, and the amount of resources used, all seemed to have some common things align, and some special treatment to the broken amounts of help certain weapons did.

Any armor works, but the armor I recommend the most is Wooden as a start, but use whatever mineral armor you think helps more. Heavily recommend running full sets only, as their bonuses are very helpful. Along with things that helped wonders, Cloud in a Bottles can help you jump out of danger if your runway is too cluttered. Magic Mirror works if you want to do that kind of loop too. Finally, as for weapons that ripped King Slime up, 2 of them destroyed him quickly. Grenades and Shurikens. Heavily recommend running those if you feel confident enough with your aim and spacing.

Last thing before I end the King Slime notes, this boss has never truly given me much of a challenge, but it can still beat me when I am not fully prepared for it. A tip from me to you is to just be fully ready for the battle before actually summoning him. Gives you a better shot at having your stuff when you need it.
Another thing that can help out for anyone playing multiplayer: DO NOT GROUP UP.
This won’t cost you a boss fight, but I would still recommend that all players active for the fight in multiplayer have something to do no matter whats going on in the battle. You can have some focus on clearing your path while others attack, whatever works for you all, but do not group up. One wrong step, and in the worst situation available, all of your friends will group up to do something or hold up somewhere, and King Slime will teleport on top of you all for a load of free damage to all of your team’s HP.