Brotato

This is quite a comprehensive guide I may put into the general "win on danger 5" achievement, but I found this character quite hard personally, but not as hard as the ones I still don't have lol

To unlock King, you must hold 3 Tier IV (red) weapons at once, obtained by combining two of the same tier III weapons, or purchasing from the shop, which will also unlock the achievement


King has the traits

• +50 Luck
• +25% damage with tier IV weapons held
• +25% attack speed with tier IV weapons held
• +5 max HP for each tier IV ITEM you hold
• -15% (lose 15%) damage for each tier I weapon held
• -15% attack speed for each tier I weapon held
• -2 Max HP for every different tier I item you hold

Long trait list, and can be hard to navigate.

Danger 5, no handicap, suggestions;
First off, it is naturally RNG based, it took me more than a dozen attempts.
Starting weapon:
The +50 luck is great here. You start being able to choose a tier II weapon. I tried ethereal axe first multiple times, but the class bonus of -armor hurt too much. I chose the Rocket launcher and cleared on the first go.

Items
You do not have to avoid tier 1 items, BUT do pick items that are common, and outweigh the -2HP, such as 'broken mouth +5HP', 'Cake +3HP', 'Jelly' among others, as the -2 only counts on the FIRST item, and not successive items, but again its a risk since RNG is good like that.
Silver bullet if you are lucky enough to find is a must buy, for the elite bosses if you are unlucky enough to have 3 of them during your run.
Tier IV items are dropped by bosses, or sold in the shop in later waves. Dropped items are random but most offer no downsides, and should be safe to take, besides possibly 'torture' depending on your build.

Weapons
Same goes for weapons, the game tends to offer similar class weapons, I did another playthrough while writing this to test, and was offered tier I 'plank' and 'shredder' each, and used them despite the -30% damage. The splash damage is great, and I was able to purchase duplicates for each after round 2 and round 3 to get tier II of each. I managed to get a tier IV plank after wave 7.
Focus on getting your first tier IV as early as possible. the increased damage and attack speed are insane, ideally before wave 10 before elite bosses start.

Stats
Depending on your weapons, Ranged is necessary for the rocket launcher, shredder, nuclear launcher etc. Elemental for plank and power fist.
The best stats to aim for when levelling up are going to be hitting 10HP Regen, ~10 speed, some harvesting, range and engineering. A minimum of 8 armor by first boss wave to soften the blow, and a touch of dodge if you can. The HP regen should offset needing dodge but using WASD to dodge red orbs or casting areas is genuinely the best way to stay alive.

Gameplay
Bunch the opponents, plan your routes, and WASD strafing the shit out of the heavy hitters in round 6 are your best bets, save consumables until you really need them. Wave 7 has the egg spawning enemies, so speed helps to reach them before they can spawn. Wave 9 is a always a horde wave, good time for XP farming, so try and leave as many materials on the floor in wave 8 to receive 2x materials in wave 9, weak enemies + explosives = $$$.
Fast reactions for bosses is key, dodge the casting attacks and the rush attacks as best as possible, and plan heals.

Keep trying above all, it isn't impossible!

Completing wave 20 with King unlocks this achievement, but also